via AFMS Show
Nashville, Tennessee July 11, 1999
- Winning Adult Articles (in 0rder of Finish)
- Chronologic and Stratigraphic Nomenclature ..... by Erich Rose
- Ishpeming's Jasper Knob ..... by Walt Vogtmann
- Mazon Creek: Secrets Unearthed ..... by Jeanine N. Mielecki
- Out of Sight Hiddenite ..... By Marianne Luther
- Trilobites of Northwest Georgia ..... by Bill Montante
- The Supercontinent Cycle ..... by Steven Wade Veatch
- Color Enhancement of Topaz ..... by Dee Purkeypile
- All's Well at Wiley's Well ..... by Glen Mackenzie
- Mineralogy of the Jomac Mine San Juan County, Utah ..... by Patrick E. Haynes
- Pleochroism and the Dichroscope ..... by Michael Kessler & Robert E. Sanger
- Add a Bit of Salt to Our Collection ..... by Marvin Lundquist
- Hot Rocks ..... by Doug Moore
- Vanadinite ..... by Clay Williams
- More of the Rays of Big Brook ..... by Robert Dann & Sylvia Seda Pucci
- Topaz Mountain ..... by Terry Vasseur
- More About Polishing ..... by Okley Davis
- Bauxite ..... by John Dickson
- Learning to Use It or Lose It ..... by Dick Rantz
- A Hunting We Will Go ..... by Mary Jane Boutwell
- Nellie' Story ..... by Doris Cullom
- Snowbird Mine Field Trip ..... by Ruel Janson
Chronologic and Stratigraphic Nomenclature
by Erich Rose
From Newsletter of New York Paleontological Society 4/98
(1st Place, 1998 AFMS Adult Article Contest)
So what's the difference between the Silurian Period and the Silurian System? Do you have a clear idea what constitutes the Helderberg Group as opposed to the Helderbergian Stage? Are you confused when you see one map that includes the Oriskany Sandstone and another showing the Oriskany Group? If you like to read as much about geology and natural history as you like to collect fossils themselves then you will have run into a variety of such terms. And yes there are definite difference between what is meant by period versus system or group versus stage. It can be very helpful to know why scientists use these different terms even when apparently discussing what appears to be the very same thing. As you collect and catalog your fossils you will use these terms- when labeling your collection so it is best to have a good understanding of the specific meanings these terms have and the proper contexts in which they are used. Just as I did in my last article on Taxonomic Nomenclature [see the March, 1998 issue of the Newsletter], I would like to help clarify some of these more basic terms you will run into or need to use as you study paleontology and build a fossil collection.
Geochronologic and Chronostratigraphic
Nomenclature: the Time Units
Geologists and paleontologists describe the history of the earth (geologic time scale) in two ways: relative and absolute time. Relative time is simply the concept that A came before B and B before C and so on. For a long time this was the best that geologists could do although many attempts at working out the actual age of the earth had been attempted. With the 20th century and scientific discovery of such things as radioactive decay and magnetic reversals scientists have gained the tools needed to make actual, or absolute, measurements of the age of the earth or more precisely, the age of various rocks found within the crust of the earth. [Ed Note: For more on absolute and radiometric dating, see our series by Maria Vogt in prior issues of the Newsletter]. But since some of the "absolute" dates for events in earth history are still controversial, or yet to be determined, scientists still describe them in both relative and absolute terms. There is a place for both.
Geologists have organized time into discrete units that they use to describe the history of the earth. They use two sets of terms, or systems, of units: geochronologic (a.k.a. Geologic Time) units are used for those intangible terms that represent relative time, chronostratigraphic (a.k.a. Time Stratigraphic) units refer to the actual rocks or strata and have a much more concrete basis in the actual geology. A good example would be to distinguish a discussion of evolution during the Devonian Period from a report on the fossils found in the Devonian System of New York. Period refers to the idea of a defined length of time while System refers to the actual stratigraphic record encompassed by that length of time.
The Geochronologic units from the largest to smallest divisions are: eon, era, period, epoch and age. An example would be.- the Phanerozoic eon, Mesozoic era, Cretaceous period. Late Cretaceous epoch and Maastrichtian age.
The chronostratigraphic units include: erathem, system, series and stage. The examples here would be: the Mesozoic erathem, Cretaceous system, Gulfian series (Upper Cretaceous) and Maastrichtian stage.
As you can see, era = erathem, period = system, epoch = series and age = stage. Note that there is no chronostratigraphic equivalent for eon.
You will also notice that epochs are referred to as early, middle or late (time units) where as series are referred to as lower, middle and upper (stratigraphic units) and both are capitalized when used formally.
When encountering different chronostratigraphic units below, the level of period/system it is important to note that different countries or continents have different standards. The European Standard is also sometimes referred to as the World Standard. North America has its own standard for some divisions. Correlation charts will often give both. If you are labeling fossils or- describing locations it is best to choose one standard and stick to it.
Stratigraphic Nomenclature: the Rock Units
The basic unit of geology is the formation. Formations are layers or sequences of rocks or other sediments that have been formally recognized by geologists on the basis of their distinctive lithology and structure and are recognizable over a mappable area or region. It is important to note that formations are not time units and can vary in age over their area. Formations are defined by their type section. The type section is usually an easily accessible road cut, cliff or other outcrop that can be referred to by others and is used to define the upper and lower limits of the formation. The location of a type section often gives its name to the formation.
Formations are often made up of one rock type although they may also be a distinctive association of rock types. Those that are made up of a single rock type will have a name that reflects that quality, such as the Manlius Limestone or Oriskany Sandstone. Where as, formations that are made up of different rock types are just called formations, an example being the New Scotland Formation that has limestone, siltstone and shale components. Note that when used formally the word formation or limestone is always capitalized. When reading the literature or maps you may encounter both terms. Generally the more recent maps or publications will have the most up to date names for local geology.
Sometimes formations are subdivided in members. Members reflect different rock types other variations within a formation and are also named after localities with designated type sections. In addition, you will also find descriptions for beds. Beds are thin, but easily recognizable, units sometimes based on fossils or other distinctive features. Sometimes a very distinctive assemblage fossils will be used as a marker bed. There are some very distinctive "coral" beds within the Middle Devonian that we have visited on field trips upstate. Beds can often help you determine where you are within a formation.
Regionally several formations may combined into larger units known as groups. Groups are sometimes divided into subgroups or combined into yet larger associations known as supergroups. Some of you may be familiar with the term Newarl Group which refers to the various rocks laid down the subsiding Newark rift basin of Triassic and Jurassic time. Some geologists now refer to the entire collection of Mesozoic basins from the Carolinas to Newfoundland as all being part of the Newark Supergroup. The centrally located and well studied New Jersey Newark Group rocks thus have lent their name to all equivalent rocks along the east coast.
The above terms are all lithostratigraphic units and are based on the rocks themselves. Another "stratigraphic" unit you will encounter is the biostratigraphic unit or zone. These are based fossils or their traces. Since it is not uncommon for a formation or member to be of different ages over aerial extant scientists will look for fossils that difine a particular time zone and whose upper and lower limits are relatively parallel over time. Sometimes even cutting across formation boundaries. These biostratigraphic units are usually named after a fossil or association of fossils that delineate them. A good example would be the various "Expgyra zones" of the Upper Cretaceous by which formations in New Jersey can be correlated with those of other Atlantic and Gulf coast formations. These fossils are sometimes referred to as index fossils and are an important stratigraphic concept to understand. Ideally an index fossil is a species whose occurrence within the stratigraphic column is limited vertically (time wise) but is found over a large geographic area. Many index fossils were free swimming or planktonic animals that spread over wide areas regardless of seafloor environment. Prime examples are conodonts and ammonites.
Lithostratigraphy and biostratigraphy are two "buzz" words to look for when doing research. Papers on lithostratigraphy are often-just about the rocks themselves and are good if you want to know more about the geology itself or need to identify the formation from which fossils were collected. They often have limited paleontological information. On the other hand if you see papers describing the biostratigraphy of a formation, you will generally find lists of species and detailed descriptions of what rock units those species occur within or may be limited to.
As you research the formations from which you are collecting, you will find that the names and rankings of rock units are often changed and revised over the years. Members become formations. Formations get divided or grouped into yet other formations. Names are dropped and replaced, etc.. A good regional example is the Kalkberg Limestone which originally was considered the lowest portion of the New Scotland Formation. Further work showed that the Kalkberg "member" was in fact a distinct lithologic unit and was thus raised to the rank of formation. Again look to the more recent maps or publications for the most up to date names.
One more term you will see used these days is facies. Facies are sediments deposited in a similar environment that have a typical lithology (lithofacies and/or paleontology (biofacies). Similar facies can occur across numerous formations and time period or are repeated in cycles. A good example is the various facies of the "Catskill Delta" that can be traced westward through progressively younger rock units across New York State as the shoreline moved westward during Middle and Late Devonian time. By learning to recognize different facies types, you will be better able to interpret and recognize the formations from which you are collecting. You will also learn that certain types of fossils are to be expected in one facies but not another.
Age and Rock Units for Your Collection:
Now that you have an idea of what these different terms mean here are some examples of how you can use them in your own collection.
- If you have organized your collection around fossils from different time periods, you will want to use "geochronologic" terminology to describe your collection. Example: Trilobites of the Devonian Period from North America and Africa.
- If you have organized by a more regional theme, you may want to use more specific "chronostrativsaphic" or "lithostratigraphic" nomenclature. Examples, respectively: Fossils of the Devonian System in New York State or Fossils of the Hamilton Group ('Middle Devonian) of New York State.
- When labeling the age of your actual specimens, use "chronostratigraphic" units. Example: Helderbergian Stage, Ulsterian Series, Devonian System. This would usually be simplified to: Helderbergian Stage (Lower Devonian).
- When recording geologic information, use "lithostratigraphic" units. Example: Ravena Member, Coeymans Formation. Helderberg Group, Lower Devonian.
You may want to begin with the most specific and work up as in the examples given or switch it around starting with the larger more inclusive units. It doesn't matter as long as you make your system of labeling consistent. In this way anyone reading your notes or catalog will easi1y understand what you mean and not be confused by mixed methods of notation. Also don't feel like you must always be so exacting. Don't let a lack of detailed knowledge of geology prevent you from labeling your fossils. Write down what you do know and as you learn more you can always go back and fill in the blanks. Your collection will thus grow in more ways than just the quantity of fossils.
As I have discussed in earlier articles, proper labeling of your fossils is one of the most important and valuable aspects of your collection and it is important to have a good understanding of terminology and nomenclature. Along with all of your various field guides and other books used for fossil identification, it is handy to have a general reference on geology and earth history as well as an up to date geology or earth sciences dictionary. Below you will find several books that I used for this article and which I highly recommend.
So have fun collecting fossils, reading them books and learning more about the amazing history of this here big spinning chunk of rock.
Levin, H.L., 1996 (5th edition) The Earth Through Time, Saunders College Publishing, NY
Parker, S.P., editor in chief, 1994 (5th edition), Dictionary of Earth Science, McGraw-Hill. NY
Parker, S.P., editor in chief, 1994 (5th edition), Dictionary of Geology and Mineralogy McGraw-Hill, NY
Ishpeming's Jasper Knob
by Walt Vogtmann, Editor of The Rockpile
From The Rockpile, 1/98
(2nd Place, 1998 AFMS Adult Article Contest)
"World's Largest Gemstone"
Though tourist literature calls it the "world's largest gemstone," tourists do not beat a path to its site. Indeed, this potential rockhound Mecca is infrequently visited by anyone, despite its exquisite beauty and accessibility.
The site is Jasper Knob, aka. Jasper Hill, a unique geological occurrence in Ishpeming Michigan, a city of 7,200 in the state's upper peninsula. Jasper Knob is literally a small mountain of jaspilite - about 25 million tons of it
Jaspilite consists of alternating layers of deep red jasper and bluish-black hematite and is the type of rock that attracts rockhounds with an interest in lapidary. Their attraction stems from the fact that jaspilite takes an excellent polish and its alternating layers, sometimes folded, bent and twisted, can present interesting patterns that show to good advantage in polished specimens.
The jasper is a chalcedony, a very fine-grained form of quartz, with disseminated red, microscopic platelets of hematite. Jasper is sometimes identified as chert. Hematite is an iron oxide and an ore of iron. Jasper has a hardness of 7 on the Mohs scale, and hematite a hardness of 6. Bound together as jaspilite rock, it is a material which is both hard and tough.
Jasper Knob, owned by the Cleveland-Cliffs Iron Company, a subsidiary of Cleveland-Cliffs Inc, is located in a residential area at the southeast edge of the city near the intersection of Hill and Jasper streets. The knob rises to the north from Jasper St. and can be accessed through a five-step opening in a jaspilite-block wall (apparently constructed from jaspilite cut out of the hill when the street was built). From there, an easily hiked, shady, pine needle path rises at an incline of about 30 degrees for 250 yards to the top, about 375 feet above street level.
Though Jasper Knob is covered with soil and vegetation on all sides, its top, an area measuring about 100 x 75 feet, is about as bald as the proverbial bowling ball, and almost as rounded. Here, at its top, the jaspilite does indeed look like a giant, polished gemstone, with its intensely folded alternating red and black bands beautifully contoured and semi-polished to a luster. In viewing these "elephant backs" of jaspilite, one can easily visualize a once larger mountain of jaspilite being scraped, shaped and polished by the successive glacial movements that once moved across this land.
And beyond the surprising jaspilite outcropping at the top, because the north face of Jasper Knob is actually a bluff which falls off abruptly to the valley floor 500 feet below, one gets an excellent view of the city of Ishpeming and the headframes of the old Cliff Iron Mine in the distance.
Geologically, Jasper Knob is old. It is a part of the Negaunee Iron Formation in the Marquette Iron Range. The Negaunee Iron Formation is of Middle Precambrian origin. The Precambrian period involves 85-90% of all geologic time and its beginning is placed at between 4,500 and 3,800 million years ago, extending to 600 million years ago. Though the geologic processes are not fully known, the Negaunee Iron Formation is believed to have involved metamorphism of Precambrian sedimentary rock.
Cleveland-Cliffs geologists offer the following technical description of Jasper Knob and theories about its origin:
Classic exposures of the jaspihtic upper part of the Negaunee Iron Formation may be seen on Jasper Knob. These exposures are in the central part of the Marquette synclinorium, north of the major fold axis of the district.
The iron-formation characteristically has alternating thin beds and lenses of steel-gray, darkblue-gay, dark-gray or black specular hematite and bright red hematitic fine-grained cherty quartzite. Beds commonly range in thickness from a fraction of a millimeter to about 2 centimeters, and fine internal laminations can be seen in the thicker layers. Specularite plates are strongly oriented parallel to bedding in the hematitic layers. Excellent colored illustrations of this rock have been published in U. S. Geological Survey Monograph 28.
Folds with drag folds on their limbs, and themselves constituting drag folds on the limb of a still larger fold, are strikingly shown in most exposures. Fold axes are horizontal to gently plunging. In cross section the south limbs of individual anticlinal drag folds commonly are longer than the north limbs, indicating that the major synclinal axis passes south of Jasper Knob.
Small breccia zones occur in the iron-formation at this locality. Along them, the comparatively brittle reddish cherty (jasper) layers in particular have been fragmented. Fractures have been healed mainly by crystalline hematite. Some of the breccia, zones may correspond in orientation to axial plane cleavage.
Two principal theories have been advanced for the origin of the jaspilitic iron-formation at Jasper Knob. One theory advocates oxidation of a sideritechert iron-formation during the post-Negaunee erosional interval and its recrystallization to specularite-quartz during the late middle Precambrian orogeny and metamorphism This theory would account for patches of jaspilite in carbonate-facies iron-formation which are present near contacts between the two rocks, as for example in the Cliffs Shaft mine about 1/2 mile northwest of Jasper Knob.
The second theory advocates a primary origin for the iron oxide, either as depositional hematite or as magnetite derived by diagenetic modification of depositional oxides. Physically, particularly in the very even bedding, the rock here resembles magnetite-rich facies of iron-formation rather than hematitic facies, which is characteristically irregularly bedded and oolitic.
Chief geologist at Cleveland-Cliffs, Tom Waggoner, offers yet a third theory about its origins. He believes Jasper Knob originated as "hydrothermal replacement of siderite-gray/black chert with hematite for siderite and fine hematite turning the chert bright red." He further believes this took place prior to placement of the overlying goodrich (quartzite) and estimates that "the depth of the ore body is down to at least 1,000 feet".
Historically, jaspilite has been mined as an ore of iron, though it is low grade and requires berieficiation through a concentration of its ferrous content. Such beneficiation of iron ore was begun in the Marquette Iron Range (of which Jasper Knob is a part) in the 1950s. Jasper Knob, however, has never been mined, according to Dale R. Hemmila, an Isliperningbased spokesman for Cleveland-Cliffs, "because it is too low (about 30%) in iron content".
As a lapidary material, jaspilite shows up especially well in large objects such as bookends, but it is also used to make jewelry (pendants, bola ties, belt buckle insets, and the like), and many rockhounds appreciate having a few pieces of jaspilite in their rock and mineral collections.
Lapidaries wishing to exhibit their work competitively, however, should take note that the American Federation of Mineralogical Societies has discredited use of the term jaspilite as a designation of a lapidary material. It recommends use of the more cumbersome nomenclature banded hematite and jasper, and AFMS Uniform Rules judges could deduct points for the labeling of material as jaspilite in competitive exhibits. The AFMS recommendation does not seem to have been adopted widely by the rockhound community, however, and use of the term jaspilite continues to be the norm.
As to the declaration at the top of this article that Jasper Knob is "infrequently visited," admittedly, there is no verifiable proof Yet, on two separate summertime visits in 1996 and 1997, no other visitors were found at the site, the area was remarkably litter-free (suggesting few visitors), there were no tell-tale signs of any collecting activity, and a couple of the residents on Jasper St., when queried, said they rarely saw anyone visit the site. One might think that the site is fenced off and posted as "No Trespassing". Not true.
What is true is that there are no road signs anywhere giving directions to Jasper Knob, and even when standing in its shadow, you wouldn't have a clue to where it was. The site is not marked. Even with a map and directions from the state tourist office at Marquette, on a first visit help from one of the residents of Jasper St. was required to find it. And don't ask just anyone in Ishpeming at random for directions to Jasper Knob. Chances are the response will be, "Never heard of it." In truth, the "world's largest gemstone' is hardly known in its home town. And obviously, the Cleveland-Cliffs corporation is not in the tourist business.
Given that Jasper Knob is a corporately-owned property, access to the property is totally within the discretion of Cleveland-Cliffs. When asked about its accessibility to the public, Mr. Hemmila said that the company "maintains an open lands policy, so within that policy there is access to Jasper Knob."
And, of particular interest to rockhounds: "Is Jasper Knob open to the collecting of jaspilite?" Mr. Hemmila replied, Sampling within reason is OK" One would take that to mean that the collecting of specimens for personal use, with hand tools only, is acceptable to Cleveland-Cliffs. Rockhounds should be elated to learn that. But be prepared for a lot of hard work - for Jasper Knob does not give up its jaspilite easily.
- Cannon, William F., "Michigan Iron Country," Rocks
& Minerals, May/June 1983, Vol. 58, No. 3. p. 120.
- Geology Department, Cleveland-Cliffs Inc,
"Description of Jasper Knob, Ishpeming, Michigan," (undated).
- Heinrich, E. Wm., The Mineralogy of Michigan,
Department of Natural Resources, Geological Survey
Division, Bulletin 6, 1976.
- Hemmila, Dale, R. Personal Communications dated
March 24 & April 10, 1997.
- Kelley, R.W. and Farrand, W.R. The Glacial Lakes
around Michigan, Geological Survey Bulletin 4, 1967,
Michigan Department of Natural Resources.
- Kemp, Jean., "Where to Go; What to See," Rocks &
Minerals, May/June 1983, Vol. 58, No. 3. p. 139.
- MacFall, Russell P., "Michigan and the Lapidary,"
Rocks & Minerals, May/June 1983, Vol. 58, No. 3. p. 136.
- Poindexter, O. Floyd; Martin, Helen M.; and Bergquist,
Stanard G., Rocks and Minerals of Michigan,
Department of Conservation, Geological Survey
Division, Publication 42, 1951.
- Wilson, Steven E., Collecting Rocks, Minerals and
Fossils in Michigan, Geology Division Pamphlet 6,
Michigan DNR, p. 7, (undated).
Mazon Creek: Secrets Unearthed
by Jeanine N. Mielecki
From The Badger Diggin's, 12/98
(3nd Place, 1998 AFMS Adult Article Contest)
When it comes to fossil collecting, I'm the persistent type. So, after having found less than a half-dozen fossils in three visits to the Mazon Creek area in northeastern Illinois, I didn't get discouraged. I decided to find out what others knew that I didn't, by making "field trips" to the Mazon Creek Open House held at Northeastern Illinois University (NEIU), the Internet, a local rock shop, and by digging into a mound of books and literature. Here's what I discovered.
Mazon Creek fossils from the Pennsylvanian Period, 300 million years ago (mya), are primarily found in Grundy, Will, Kankakee, and Livingston counties. The area, world-famous as a lagerstrettren for the exceptional diversity and preservation of its fossil record, first captured the attention of the scientific community in the 1840s, with the discovery of terrestrial plants and soft-bodied animal in local river banks. Commercial coal mining removed the overburden above the Frances Creek shale, where these fossils are found, on a large scale from the 1870's through the 1960's, which brought more exciting discoveries to light.
When the Peabody Strip Mine, known today as Pit #11, opened circa 1945 between the towns of Braidwood and Essex, the discovery of softbodied marine animals this time rocked the scientific world. In 1958, Francis Tully found something highly unusual, brought it to the Field Museum of Natural History for identification, and became one of the great names in amateur paleontology. The Tully Monster, tullimonstrum gregarium, is the Illinois state fossil and found nowhere else. Today, important new discoveries increasing our knowledge of past life continue to be made by both amateurs and professionals, one of them could be you!
North America was a very different place 300 mya. Much of the land was covered with equatorial swamps, river deltas, and warm, shallow seas. The Mazon Creek area was a river delta teeming with the life forms of all three ancient environments.
Depending on where the fossils are found, they will be from one of the three zones forming the total Mazon Creek Biota. Fossils of the Essex faeies, found south of the town of Braidwood, are the remains of near-shore, marine life. Fossils of the Braidwood facies found to the north consist of two subbiotas: the Braidwood Fauna, the remains of the animal inhabitants of the nonmarine portions of the swamp; and the Braidwood Flora, the plant remains of the terrestrial lowlands. A site yielding fossils of plants and insects generally will not be a place to find mollusks and jellyfish, and vice versa. Yet within the limits of Pit #11, both plant and animal fossils can be found.
Mazon Creek fossils ate found inside siderite (iron carbonate) concretions that are fine-grained; round, oval or flattened; and rusty orange, brown, gray or dark red. Texture and color will vary by location, even when collecting sites are just miles apart.
Mazon Creek animal fossils include fish, crabs, shrimp, clams, centipedes, millipedes, worms and jellyfish. Plant remains include the bark, roots, steins, fronds, leaves, seeds or cones of lycopods (clubmosses), seed or spore ferns, calamites (horsetails) and mote. Trace fossils can be animal tracks, trails and burrows, eggs, fish scales or coprolites. Rare amphibians, insects and spiders have been found. Although they evolved during the Pennsylvanian, remains of reptiles have not been discovered here.
The taphonomy (the process that takes place from the time a plant or an animal dies to when it is buried) of these fossils remains somewhat of a mystery. Two theories exist. One is the plants and animals that died along the river were swept into the coastal bay, where they sank to the bottom, and were rapidly buried in silt. Bacteria began decomposing the remains creating carbon dioxide which combined with iron in the groundwater to cement the silt.
Or, the fossil concretions could have been created when tropical storm surges flooded the area many times over the ages, encasing the plants and animals in a thick, iron-rich layer of mud and silt.
Years ago, opportunities to collect in the Mazon Creek area were abundant; this is not true today. Many mines and spoil piles have been leveled. Others sites require the landowners' permission, which may be hard to obtain due to legal issues. A permit is necessary to collect around the cooling pond for the Braidwood Nuclear Plant, where the sites at Pit #11 are located.
When collecting in the field, it pays to "think small". While fossil-bearing concretions can range in size from more than one foot to less than an inch, many excellent specimens I've seen on display are on the smaller side including a one-inch concretion containing a scorpion.
Fragments of concretions also can contain attractive fossils. If you find a piece containing something really good, like a tully monster(!) or an insect wing, be persistent. The counterpart may be a few or many feet and hours of work ahead.
Many of the concretions may not contain quality specimens or anything at all. One expert, who estimates he has collected 500,000 concretions since 1973, told me, only 5,000 of these have yielded good specimens. Although the chance of finding a magnificent specimen may seem daunting, it's the quest for knowledge and the thrill of the search that keep me coming back.
I have also learned that I made a common error when trying to split open my concretions; I smashed them with my hammet, ruining several of my most promising rinds. If the concretions don't open with a few gentle taps of the hammer (do this in the palm of your hand and if it hurts, that's too hard), use the freeze-and-thaw method: place the concretions outside over the winter in a plastic bucket filled with water, then try opening them again in the spring. Several years may pass before many of them open (or not at all); one of my concretions recently split open after a five-year wait to reveal a seed fern stem and seed.
There is also the -fast- way: cut the bottom off a plastic, gallon-size bottle, put the concretions inside, fill with water, place it in the freezer for a few days, then take it out for a few days. Do this a dozen times or so before trying to open the concretions again.
In addition, concretion look-alikes, ironstained, glacial pebbles and pieces of sandstone or shale, are abundant in the field. To avoid hauling home more "duds" than necessary, keep in mind that sandstone is generally paler in color and not as finely-grained as siderite, and shale tends to be angular in shape.
Some experts recommend collecting only concretions that have already begun to crack, so that they can be easily split open. Others recommend picking up anything that looks interesting. I favor the latter. Time in the field is limited; once you get home, you'll have plenty of time to examine and enjoy your finds.
Speaking of enjoyment, while the Mazon Creek area is not "hardhat" territory, common sense combined with a few safety precautions can prevent your marvelous adventure from turning into a disaster. Before leaving for the field, prepare a checklist of items to bring and make arrangements to go with someone. Once you are there, stay within eyesight and hearing distance of each other.
It's likely there will be few trees to provide shade at Pit #11 or other Mazon Creek sites. Sunburn, heatstroke and dehydration are common potential hazards in the field. Another is insect bites or stings. The sun can be hot and drying, even on the coolest days of spring, and the wind abrasive. Always wear a wide-brim hat, a longsleeve shirt and long pants in bright colors (the easier to be seen in the case of an emergency), leather work gloves, heavy cotton socks and hiking boots. Tuck your pant legs into your boots if possible. Bring waterproof sunscreen lotion and lip balm, both preferably SPF 25+, and insect repellent. Check the weather report the night before or the day of your outing. Rain or shine, having raingear and a warm jacket handy is highly recommended. Shivering in cold weather or hot is always a sign that it's time to go home.
Whether you are going on a full- or halfday trip, the necessity of bringing lots of water, drinking it, and resting in the field cannot be over emphasized. Be sure to take a good, long drink of water every halfhour, and a short, 10- to 15-minute rest every hour or two. Don't rely on caffeinated and carbonated beverages, because these can be dehydrating. When bringing food, I prefer wet, juicy items like fruit, vegetables and non-mayonnaise salads to eat for a hydrating -pick-me-up".
Leave your heavy-duty digging tools at home, concretions in the Mazon Creek area are found through surface collecting. What you want to bring are: a large plastic bucket or canvas collecting bag, a garden trowel, a small ice pick, chisel or screwdriver to pry concretions from the soil, a hand lens, a notebook for recording your finds and a rock hammer.
Split concretions can be fragile. You may want to bring zipper-lock plastic bags and paper towels to wrap them. Other items to consider bringing: a disposable-camera should you make that find of a lifetime, and a whistle to be better heard should you get lost.
Remember to keep your eyes on your surroundings, as well as the ground. Look ahead for large rocks and branches. Think twice before climbing very far up the bank of a spoil pile, especially when it consists of loose gravel and soil, or searching close to the water's edge.
After a rainstorm, slopes in the Mazon Creek area can be very slick. Falls and spills leading to injury easily can happen. Should you slip, try not to fall hands first or go downhill feet first. Instead, land on your rear cushion, lift your hands and legs up and slide down that way. You may literally escape injury by the seat of your pants a small price to pay. Remember, safety first no fossil is worth placing yourself in harm's way.
One more tip: Eroded gullies are the best place to start looking for concretions, and after a heavy rain, the best time. Good luck and have a fossiliferously rewarding time!
For more information on field trips to Pit #11, conducted by The Mazon Creek Project of NEIU, send a selfaddressed, stamped envelope to:
1228 N. Raynor Ave.
Joliet, IL 60435
C/ Mazon Creek Project
Keys to Identify Pennsylvanian Fossil Animals of the Mazon Creek Area. Earth Science Club of Northern Illinois (ESCONI), 1989.
Keys to Identify Pennsylvanian Fossil Plants of the Mazon Creek Area. ESCONI. 1986; reprinted 1994.
The Wilmington Coal Fauna and Additions to the Wilmington Coal Flora. George Langford. Esconi Associates. 1963.
FOSSIL NEWS: The Journal or Amateur Paleontology. Gina Wysocki. Mazon Creek Madness!!! October 1998.
Mazon Creek Guide Brochure. Prepared by The Mazon Creek Project. NEW Department of Earth Sciences, Chicago, IL.
Illinois State Museum Website. www.museum.state.il.us
Discovering Fossils. Frank A. Gar
and Donald S. Miller. Stackpole Books 1998.
Simon & Schuster's Guide to Fossils,
Paolo Arduini and Giorgio Teruzzi Simon & Schuster Inc. 1986.
Out of Sight Hiddenite
by Marianne Luther, member of CLGMS
From Money Statements 9/98
(4th Place AFMS 1998 Adult Article Contest)
When I expressed an interest in researching a somewhat out of the ordinary, obscure mineral, a friend suggested that I might give hiddenite a try. At first I thought he was joking, but he assured me that it is a real gemstone and definitely worth looking into. I immediately consulted a couple of books on minerals and gems, but my search was in vain. Hiddenite was not mentioned in the index of either book, and I again began to doubt the existence of the mineral. When I turned to my dictionary in desperation, I found out that it is "a transparent yellow to green spodumene valued as a gem."
The operative word was spodumene. Once I had found that out, it was much easier to locate scientific information on hiddenite, although some of the more interesting historical data came from various publications provided by a kind Clear Lake Gem & Mineral Society member.
Hiddenite, the gem, comes from Hiddenite, a city in Alexander County, North Carolina, and both are named after William Earl Hidden, a mineralogist, contributor to scientific bulletins, mineral dealer, and mining consultant from Newark, New Jersey. Mr. Hidden came to North Carolina, because Thomas Edison had sent him there to search for platinum that might possibly serve as filament for his recently invented light bulb. He was not successful in his quest for platinum, but he made the acquaintance of J. Adlai D. Stephenson (possibly an ancestor of the 1952 presidential candidate). Stephenson gave Hidden some green gemstones found in an emerald deposit in Stoney Point (later renamed Hiddenite), North Carolina. The stones had been tentatively identified as diopside, but they were very cleavable and splintery, which are characteristics of spodumene. When Stephenson received no reply from a well-known Pittsburgh mineral collector to whom he had sent some of the material, he turned to Hidden for help in the identification of the mineral. Hidden, in turn, sent the specimens to Professor J. Lawrence Smith, a renowned mineralogist in Louisville, Kentucky. Smith determined that the crystals were a green phase of spodumene and named them hiddenite for the man who had sent them to him, not for the discoverer. To Smith, the appearance of the green spodurmene did not come as a total surprise, since he was aware of a yellowish spodumene that had been found in Brazil in 1877.
Hidden reported his failure to locate platinum to Edison back in New Jersey and promptly returned to North Carolina in 1880. As manager of the mine, he proceeded to dig up the emerald area near Statesville. The Emerald and Hiddenite Mining Company continued to operate until 1888 and produced approximately $9,500 worth of hiddenite. The largest stone, a 2.5 carat gem, was sold to A. C. Hamlin, who had it set in a necklace and gave it to a Hamlin wedding party member. Most emerald and hiddenite crystals found at the North Carolina site were located in the soil above the bedrock, which consisted of a highly metamorphosed gneiss, quite contorted and shot through with parallel strips of small pegmatite veins.
Overall, the hiddenite deposit turned out to be much less extensive than anticipated and failed to produce enough stones to pay for the mining operation. Over the years, several additional mining efforts were attempted and abandoned, and during those attempts, only one good pocket of the mineral was found. According to reports, the find was the size of a football and contained twentyone specimens of gem quality hiddenite, weighing a total of 492 carats. At the present time, the public is allowed to collect specimens at the Hiddenite site, but no commercial mining is in progress.
Although chemically simple (lithium aluminum silicate), spodumene comes in many hues ranging from colorless to white, yellow, lilac (referred to as kunzite in honor of George F. Kunz, a gemologist for Tiffany), and green. It is the green variety that is most controversial. The basic ingredients for spodurnene (LiAlSi2O6) are in ample supply, but hiddenite is distinguished by its rarity. Spodumene must also contain chromium (Cr) to be true hiddenite; otherwise the crystals are simply a light green spodumene. Therefore, according to most sources, the name hiddenite should be applied only to the emerald green spodumene, not the more common pale green varieties. Different sources disagree not only regarding what should be rightfully named hiddenite but also its location. Conservative sources insist that true hiddenite comes only from the Hiddenite mine in North Carolina, while the more liberal sources claim that all green spodumene is hiddenite and that the gemstone is also mined in the Malagasy Republic, Brazil, Madagascar, Myanmar (formerly Burma), the former USSR, and Sweden.
Since hiddenite is a member of the spodumene family, it possesses its typical physical properties, such as 6.5 to 7 hardness. heaviness, and perfect cleavage parallel to the vertical prism, and transparency or translucence with vitreous luster. It is a trichroic mineral which, when viewed from different directions, appears bluish green, yellow green, and emerald green. Hiddenite has a monoclinic crystal system, a toughness of 3, a specific gravity of 3.18, no characteristic inclusions, and an uneven splintery fracture.
Today hiddenite is extremely rare. The largest fine stone on record, the jewel from the "Hamlin necklace," can be viewed at the Harvard Mineralogical Museum. Other notable hiddenite exhibits are at the University of South Carolina in Columbia; the Colburn Museum in Ashville, North Carolina; the Smithsonian in Washington D.C.; the American Museum of Natural History in New York; and the British Museum in London.
Arem, Joel. Gems and Jewelry.
Arem, Joel. Rocks and Minerals.
Clark, Andrew. Pocket Guide to Minerals.
Deeson, A. F. L., ed. The Collector's Encyclopedia of Rocks & Minerals.
Hamilton, W. R., A. IL Woolley, and A. C. Bishop. The Henry Holt Guide to Minerals, Rocks, and Fossils. New York: Henry Holt and Company, 1974.
Hurlbut, Cornelius S. Minerals and Man. New York: Random House, 1967.
Liddicoat, Richard T., Jr. Handbook of Gem Identification. Gemological Institute of America, 1962. Identification.
Parsons, Charles J. Practical Gem Knowledge for the Amateur.
Pough, Frederick H. "Some Hiddenite History." Lapidary Journal, February 1993.
Pough, Frederick H. "Speaking Further of Spodumene." Lapidary Journal, March 1993.
Pough, Frederick H. A field Guide to Rocks and Minerals.
Prinz, Martin, George Harlow, and Joseph Peters, ed.
Simon & Schuster's Guide to Rocks and Minerals.
Schumann, Walter. Handbook of Rocks Minerals, and Gemstones. New York: Houghton Mifflin Company, 1985.
Tindall, James R. and Roger Thornhill. The Collector's Guide to Rocks and Minerals. New York: Van Norstrand Reinhold Company, 1975.
World Wide Web: http://www.gemhut.com/hidden.htm
Trilobites of Northwest Georgia
by Bill Montant
From Cobb-L-Stones 10/98
(5th Place, 1998 AFMS Adult Article Contest)
Traveling through time to Rome, GA and the Coosa Valley
Join me on a journey of geologic proportions. Our destination is an area west of Rome, GA known as the Coosa Valley. By car, it is not more than 90 miles from here in Atlanta, but we will not be driving. Distance is not the important diminution, it is time. Our vehicle is a time machine. Our destination in time is the Middle Cambrian Period - 530 million years ago. We depart today at 8 AM.
Every second that we travel, we turn back the clock 1000 years. Beginning in the Cenozoic Era:
- After 2 seconds we reach the birth of Christ.
- In 30 seconds we see the early human-like creatures walking upright.
- It takes us 18 hours traversing the Cenozoic before we enter the Mesozoic Era - the age of dinosaurs.
- For the next 45 hours we span 160 million years ever-watchful overhead for flying reptiles and cautiously work our way around an occasional Stegosaurus,
Tyrannosaurus Rex and the giant Brontosaurs; giant marine reptiles dominate the oceans.
- We now enter the Paleozoic Era after traveling in our time machine for 63 hours and 32 seconds - nearly 3 days.
The Paleozoic Era spans 345 million years and is subdivided in to seven periods. Our destination again is the middle of the Cambrian Period - 530 mya. It takes us another 3-1/2 days to get there! We reach our destination -the valley west of Rome - after 6 days and 3 hours. It is now noon on Monday. Just in time for lunch, but there is one problem. We are under water! To borrow a line from Dorothy in the Wizard of OZ, "Toto, this doesn't look like Kansas any more." What's more, all the while we've been time tripping, the earth beneath our feet was moving.
You all know where Georgia was when we left. During the Mid. Cambrian, North America was tilted on its side straddling the equator. Florida and the Georgia coast was a land mass off the coast of what is now Africa. Most of the North American continent was covered by a shallow sea. What we call the Coosa Valley is now the sea coast; part of the continental shelf.
In the Cambrian seas we encounter for the first time an abundance of well preserved and clearly identifiable fossils. Land-based fossils are unknown Few fossils are found in strata earlier than the Cambrian.
With one exception, the phylum Bryozoa, every phylum with hard body parts (and any that locked hard parts) made their first appearance in the Cambrian. A few localities around the world that preserve soft-bodied fossils of the Cambrian show that the "Cambrian explosion" generated many unusual forms not easily comparable to anything today. The best known of these sites is the legendary Burgess Shale in the British Columbia Rocky Mountains. It is highly probable that the same soft-bodied creatures discovered in the Burgess shale lived in what is now Coosa Valley.
Other life forms in the mid - Cambrian were primitive brachiopods, cephalopods, sponges, corals and mollusks; Archaeocyathids resembled both cup-shaped corals and sponges but were more closely related to algae. Another unusual animal found at the Spann Farm site are of the Phylum Cnidaria (class Protomedusae) of which the only genus is Brooksella - ancestors to the modern jellyfish and sea anemone.
Trilobites are the first life forms of the class Arthropoda to appear in the fossil records at the beginning of the Cambrian Period 570 mya. They were the most durable of the arthropods. During their 345 million years, more than 10,000 species evolved. They dominated the seas for 170 million years before the first vertebrate fish appeared 400 mya. Diversity and numbers of trilobite families drastically dropped after the Cambrian. Only the four families survived into the Devonian Period. Ultimately, becoming extinct in the mid Permian Period about 230 mya. Dinosaurs were just appearing when the last of the trilobites went extinct. Trilobite fossil remains have been found on every continent.
Trilobites are more closely related to spider's than any other type of arthropod. Other living relatives include: insects, scorpions, ticks, crabs, lobsters, shrimp, barnacles, ostracods, centipedes and millipedes. Extinct arthropod groups include the eurypterids and the subject of this presentation -trilobites.
Their ability to produce a hard outer skeleton may have resulted from an increase in oxygen level in the atmosphere and sea water, and their evolved ability to metabolize or extract calcium carbonate and phosphates from the water. The outer skeleton was mostly made of hardened proteins and chitin.
Most trilobites lived in shallow seas and probably fed on decaying matter, small plants and animals, as they crawled along the sea bottom, stirring food with their many up feet and passing it toward the mouth. Others, like the Agnostids common in the mid Cambrian - were thought to be plankton eaters. Trilobites could burrow into sediment to feed or to avoid predators.
Many living after the Cambrian developed the ability to roll up into a ball so that only
the hard outer shell was exposed. In this way, various types of spines along the carapace could be used for defense. Modern arthropods (e.g. horseshoe crab) do this. In the Cambrian, only the Agnostids could do this.
Trilobites are earliest animals known to possess vision. The remarkable construction and preservation of trilobite eyes allow us to study the development of this sensory organ that in other fossilized organisms is rarely preserved. At least two types of eyes are distinguishable in trilobites. The aggregate eye may contain from 2 to 750 separate lenses. The compound eye consists of touching hexagonal calcite lenses which may number from 100 to more than 15,000. The two eyes, roughly crescent in shape, allowed most trilobites 360 degrees of vision along the ocean floor. Some trilobites, such as the Agnostids, did not have eyes.
Trilobites had one pair of antennae. These delicate appendages rarely are preserved in fossils. Similarly, rarely preserved were their many legs. They breathed through gills in their legs.
Size varied greatly from 1-3mm (<0.1 in.) to the giants of 700 mm (28 in.). Most specimens from the Coosa Valley site are small, typically ranging from 2 mm to 35mm. Some found in this area by Dr. David Schwimmer of the U/Ga Columbus, reach lengths of 100mm. (4 in.) to 125mm (5 in.).
Like other arthropods, trilobites had to molt in order to grow. Many have facial sutures across the head where the external skeleton would split to allow the animal to crawl out of its old covering. A single trilobite, over its lifetime, may have left many parts to be fossilized, but a complete specimen always represents the death of that individual. Facial sutures are important for classification and differentiation of trilobites.
Trilobites identified as coming from North Georgia:
(1) Contributions to the Paleontology of NW Georgia; pub. 62; Ga. Dept. of Mines, Mining and Geology; 1954.
Elrathiella buttsi Resse ..... Spann Farm
Elrathia ..... SpannFarm
Armonia elongata ..... Hwy 100 road cut, N. of Livingston
Asaphiscus sp. ..... Hwy 100 road cut, N. of Livingston
Coosia superba ..... Spann Farm
Blania grefaria ..... Spann Farm
Eterapsis glabra ..... Spann Farm
Tricrepicephalus cedarensis Resser ..... Cedar Bluff, Al
Coosella curticei Resser ..... 14 mi. east of Dalton, 76/225
Solenopleurella buttsi Resser ..... 14 mi. east of Dalton, 76/225 Oak Grove School
Asphelaspis hamblernsis Resser ..... Dalton-Dug Gap Church, Foster Rd.
(2) Taxonomy and Biostratigraphic Significance of Some Middle Cambrian Trilobites from the Conasauga Formation in
Elrathia antiquata (Salter) ..... Spann Farm
Baltagnostus centerensis ..... Foster Bend of Coosa River
Peronopsis cuneifera ..... Foster Bend of Coosa River
It may have taken six days to reach our destination, but we return home in just seconds. We are now in my backyard with a pile of shale and chert nodules from the two Coosa Valley sites. The way I have been so successful in extacting such a large quantity of trilobites is to remove as much matrix as the trunk of my car will hold, bring it back home and slowly, patiently, split the shale. It might take me several weeks to work through this pile. Then it's back again for another load. This is much easier and less demanding compared to sitting in a road cut under a blazing Georgia sun.
It fascinates me that in a small corner of out State we have an opportunity to dig our hands and minds into one of the most significant of paleo events-The Cambrian Period- and its relative explosion of hard bodied life forms. And finding specimens is so easy even after 530 million years!
The Supercontinent Cycle
by Steven Wade Veatch
From Pick & Pack 7/98
(6th Place, 1998 AFMS Adult Article Contest)
Pangea, the supercontinent believed to have existed some 250 million years ago when all Earth's continents were joined together, began breaking up about 170 million years ago - when dinosaurs roamed the Earth. Earth's continents are thought to be undergoing a long cycle of colliding and separating again. This suggests that the large-scale processes of plate tectonics are controlled not by chance but by a cyclical process.
Several times during Earth's history the continents have joined to form one supercontinent-- only to be later split apart into many continent; -and then rejoin to form a supercontinent once again. Earth's continents are thought to be undergoing a long cycle of colliding and separating: during the period of continental assembly continental crust collides, merges, and forms new continents; and during continental fragmentation continental crust is separated by deep rifts that become centers of new ocean basins. This cycle of assembly and fragmentation of continental crust occurs with a periodicity of 400 to 500 million years.
Pangea, the supercontinent that existed from 200 to 300 million years ago, is the latest in a series of supercontinents. Pangea began breaking up about 170 million years ago and is thought to be part of a long cyclic process that has been going on for a least a billion years. Under the immense surface area of Pangea, heat from the mantle began to concentrate in certain areas. The focussed heat, rising as heat plumes, began forcing their way to the surface. These heat plumes acted as wedges that split Pangea into smaller continents that moved away from each other. Geologists can measure this motion caused by Earth's inner heat. In some places, it is as great as a few centimeters a year - or about as fast as fingernails grow. These remnants of Pangea have been moving for 170 million years until they have reached today's familiar positions.
The Wilson Cycle
Professor Tuzo Wilson, in 1966, noted that the opening and closing cycles of the Atlantic Ocean (on the
order of every 400 to 500 million years). The supercontinent model builds upon the Wilson Cycle where
continents rift to form ocean basins and then the basins close to reassemble the continents. Margins of the
North Atlantic have undergone a series of Wilson Cycles - oceans repeatedly opening and closing during
the past billion years. Each of the Wilson Cycles that took place in the north Atlantic region occurred as
part of the breakup and reassembly of a supercontinent. Margins of the Pacific have undergone none, a
single ocean has been maintained all the time in the Pacific. The Pacific is the descendant of the
superocean that has surrounded each supercontinent.
The continents are presently approaching their maximum dispersal and the Atlantic should close again, as dense oceanic crust begins to subduct under continents, reuniting the continents in a future supercontinent surrounded by a superocean.
The Supercontinent Cycle
It is now viewed that plates have repeatedly broken and reassembled every 400 to 500 million years during the supercontinent cycle. The supercontinent hypothesis cycle is simple: a supercontinent can exist for about 80 million years before the accumulation of heat, from the mantle below, causes it to dome upward and rifts to form. After another 40 million years the supercontinent breaks apart as rift valleys grow to become new ocean basins as hot mantle material wells up through the rift to form the seafloor. The continental fragments move apart until they reach their greatest degree of dispersal, about 160 million years later. As material from the ocean floor ages it cools and becomes denser. The oldest part of the new ocean floor (the part directly adjacent to the continental fragment) becomes so dense that it sinks (subducts) under the continental crust The process of subduction, after about 160 million years, closes the ocean bringing the continents back together forming a supercontinent. The entire supercontinent cycle takes about 440 million years.
- Stages of the Supercontinent Cycle:
- Continental heating, doming and extension
- Seafloor spreading
- Continental collision and suturing
Periods of large-scale mountain building coincide with the development of a supercontinent as continents collide and rejoin. The ages of mountain ranges, produced by compressive forces that accompany continental collisions, mark the supercontinent cycle. There have been six periods of intense compressive mountain building: 2,600 million years ago, 2,100 million years ago, a period between 1,800 to 1,600 million years ago, 1,100 million years ago, 650 million years ago, and 250 million years ago. The interval between any two of these periods or mountain building is 400 to 500 million years, about the length of a supercontinent cycle. After each of these periods of mountain building a period of rifting follows, producing large numbers of rocks from magma welling up into rift cracks. These rocks date from 2,500 million years ago, 2,000 million years ago, a period between 1,700 to 1,500 million years ago, 1,000 million years ago (rifting and the breakup of Pangea). These regularities indicate supercontinents are created on a cyclic process.
Shaping Geologic History
The supercontinent cycle is the driving force for many of the most important developments in the Earth's history. These cycles have a bearing or. sea level changes since the supercontinent cycle involves the creation and destruction of ocean basins and thermal uplifting of continents - which determines the volume of the world's ocean basins and relative elevations of continents. When a supercontinent is present, the sea level is relatively low. As the supercontinent rifts apart the sea level should begin to rise as the continental segments stretch and subside. The breakup will also start to replace older Pacific-type (subducting) ocean floor - which is deeper - with younger Atlantic-type (non-subducting) ocean floor - which is shallower. Sea level should continue to rise for about 80 million years as younger ocean floor (shallow basins) makes up a greater portion of the world's ocean floor; As the young Atlantic-type oceans expand, age, and deepen, sea level should decline for another 80 million years until the Atlantic-type ocean floor begins to be subducted.
As the older Atlantic-type crust subducts the continents are brought back together -causing the sea level to rise 80 million years until the supercontinent is reassembled. Once formed the sea level should remain stable for 120 million years until the supercontinent breaks up again. These predicted sea level changes correspond with the geologic record for the past 570 million years.
During the time that sea level is low (when the world is dominated by a single supercontinent or when the continents are widely dispersed and the ocean floor is the oldest) large amounts of silicate minerals in the continental crust are dissolved and carried to the oceans. In the seawater the silicates combine with dissolved carbon dioxide to produce solid precipitates, which reduces carbon dioxide in the atmosphere. This lessens the greenhouse warming effect and the world climate is cooler.
In the past the different stages of the supercontinent cycle have also influenced patterns of weather and climate, the composition of the atmosphere and oceans, glaciation, and ocean circulation. These factors drove many biological adaptations that guided the course of evolution and the history of life on earth.
Today the continents are still moving, and in the future, new continents will form. Eventually North America and Eurasia will collide and Australia will join them forming the next supercontinent.
Appenzeller, Tim, Travels of' America, Discover, Vol. 17, no 9, September 1996, pp. 80-97
Dalziel, Ian, Earth Before Pangea, Scientific American, January 1955, pp. 58 - 63.
Earth and Sky: http://www.earthsky.com/1997/es970920.html
Nance, R. Damian, Worsley Thomas R., and Moody, Judith B, The supercontinent cycle, Scientific American, Jul), 1998
Fisher, Alfred G., 1983, The two Phanerozoic supercycles: In Catastrophes and Earth History, eds., IN". A. Bergren and John Van Covering, Princeton University Press.
Color Enhancement of Topaz
by Dee Purkeypile
From The Stone Chipper 4/98
(7th Place, 1998 AFMS Adult Article Contest)
Topaz is one of our most popular and affordable colored gemstones. Blue topaz is one of the most beautiful and commonly marketed colors of this remarkable gem. Although topaz naturally occurs in many different colors, blue topaz has dominated the jewelry market since the 1970's when a large number of deeply colored blue topaz crystals started appearing on the market. At that time there were no new mines or developments in existing mines to explain the sudden availability ofthis abundance of blue topaz. The production of blue topaz from colorless topaz with irradiation was first reported in 1957 by F.H. Pough, who was a contributing editor ofmany articles on minerals in the Lapidary Journal until only recently. Kurt Nassau, a research scientist residing in Bernardsville, New Jersey, rediscovered this information in 1974 when he was analyzing a faceted topaz that had been purported to be quartz. Since that time many hundreds of thousands of carats of treated blue topaz have been marketed by many sources. Nassau's research revealed that both natural blue and irradiated blue topaz are stable to light. This may account for its popularity with both jewelers and the buying public since of the three types of yellow to brown topaz, two fade in sunlight. Natural pink topaz is stable in sunlight but is extremely rare.
The ancient historian, C. Plinius Secondus (born 23 AD and died 79 AD during the eruption of Vesuvious) wrote an epic account of all that was known in his time and which entailed 37 volumes. Plinius reportedly gained his information by traveling and by reading over 2000 books. Some of these books discussed gemstone alterations: "Moreover, I have in my library certain books by authors now. living, whom I would under no circumstances name, wherein there are descriptions as to how to give smaragdus (emerald, in part) to crystallus (rock crystal) and how to imitate other gems: for example, how to make sardonychus (sardonyx) from sarda (carnelian, in part sard): in a word, to transform one stone into another. To tell the truth, there is no fraud or deceit in the world which yields greater gain and profit that of counterfeiting gems."
With the detonation of the first atomic bombs in the deserts ofthe American west, the course of human civilization was irrevocably changed. That change also brought along with it much experimentation as regards the effect of radiation on all objects precious or common. It was only natural that man would attempt to alter precious stones with this incredible energy source. None of the many gemstone enhancement processes used on other gemstones appears to have been used on topaz except for the dyeing of water worn pebbles in indigo dye pots.
Typically, colorless or palecolored topaz is heated to 200 to 300-degrees centigrade for several hours. The longer the stone is heated the deeper the color change will occur in the stone. The stones will turn to a yellow to brownish green to a dark brown color. These colors however are not stable and will eventually fade to clear unless the stones are irradiated. The irradiation process essentially the eliminates the yellow-brown and green colors and leaves a stable blue color which will not fade unless subjected to temperatures of 500 to 600-degrees centigrade.
Topaz is irradiated by one of three energy sources: gamma rays from the mass 60 isotope of cobalt (Co-60), high-energy electrons from linear accelerators, and neutrons from nuclear reactors. Gamma irradiation is the most common and least energy costly method. The other sources of irradiation can produce deeper blues, however, they are very energy consumptive and in the case of neutron irradiation, most often unavailable to commercial interests. Gamma cell devices are commercially available, require little upkeep and continuously produce rays over many years as the Co-60 slowly decays. The gamma rays penetrate the stone very deeply and produce uniform coloration if the stone is uniform. What little heat is generated by the exposure to Co-60 is distributed uniformly throughout the stone which significantly reduces the chance of cracking the gem material. The heat generated is a function of the time of exposure and the dosage of the radiation source. Cracking will usually be prevented if the dose is kept to less than 5-megarads per hour. The longer the topaz is exposed to the gamma source the deeper the blue can be obtained. However, the typical light blue color is the most often seen result of gamma exposure. The cooling down time for gamma irradiation is on the order of several weeks to several months as opposed to electron or neutron irradiation which may take up to a year and a haft to cool down to safe handling levels. Irradiated topaz is so common that it is one of the only gemstones that is consistently checked at U. S. Customs for excess radiation. Unfortunately, other irradiated stones have been allowed to enter the U.S. simply because Customs has not been aware of the massive abuse of irradiation with other gemstones in foreign countries that do not properly control their irradiation sources. All in all, topaz is one of our least expensive precious gems that is still in high demand because of its intrinsic and enhanced beauty.
All's Well at Wiley's Well
by Glen Mackenzi, Ecology Chair
From Diablo Diggins 12/98
(8th Place, 1998 AFMS Adult Article Contest)
Now that the long hot summer has gone away and the autumn leaves are falling, perhaps you are starting to think about winter rockhounding. That naturally leads one to think about Quartzite and walking, head down, with the warm desert sun on your back. So, what follows is a previously unpublished true story, a field trip report actually, that occurred last winter and has been lurking in a computer disc these many months. Perhaps the following will stimulate those little gray cells to start thinking in the direction of the southwest.
Ready to shake off the moss and mildew of nearly forty days of Northern California rain? You bet! Ready to get out in the desert mountains and dig in the dirt for those round agate filled treasures? You bet! Even including a few sore muscles? You bet!
That was the attitude of forty-five rockhounds attending the third Wiley's Well field trip of the Antioch Lapidary Club, to this interesting area. It is easily reached from Interstate 10, approximately sixteen miles west of Blythe, CA, at Wiley's Well Road off ramp, where there is a convenient rest stop, complete with a sanitary dump station for those needing to empty their holding tanks before a week of dry camping on the desert.
Wiley's Well Road is a wide level dirt right-of-way suitable for most vehicles including large motor homes and other RVs. Our campsite was 12 miles south, from Interstate 10. We found it severely wash boarded on our way in and were constrained to go twelve to fifteen miles per hour to avoid jarring out our back teeth and windshield! Fortunately, by the time our field trip was over, BLM had bladed the road making it a mere 15 minute jaunt to Interstate 10.
A few interesting facts associated with the Wiley's Well area are noteworthy. It crosses the historic Bradshaw Trail, early route of the famous Butterfield Stage. In late 1857, Postmaster General Aaron Brown awarded a contract (without competitive bidding!) to John Butterfield, to carry the mail between San Antonio, Texas and San Diego. Butterfield set up the exact route and stations, except that he routed things to Los Angeles instead. History does not seem to record whether this was by accident or design. The 1,476 miles took 30 days travel time. On a bi-monthly schedule a stagecoach left each terminus simultaneously. It operated between 1858 and 1861. 1 have been on some portions of the trail further west, still traceable, adjacent to the Anza-Borrego State Park, west of the Salton Sea. If Cal OSHA had been in existence at that time, it would never have gotten off the ground. Paying passengers were expected to provide a part of the pushing power at certain difficult points. Bradshaw trail east of Wiley's Well Road is a fast, easy modern day route to the village of Palo Verde on the east side of the Mule Mountains.
Our campsite was located on a huge flat stable area covered with brown "desert pavement", east of the contrasting green Black Hills Wash and handy to the Black Hills Road, our path to paradise. Our leader and intrepid wagon master was Dick Pankey, Field Trip Chairman of the Antioch Lapidary Club, aided and abetted by Betty Pankey, his wife. Dick, led this trip in 1994, 1996, and again on February 9th, of 1998 as a follow up to the Quartzite Pow Wow. Incidentally, Dick offers a slide program of his 1994 Wiley's Well field trip as a podium speaker for the CFMS. When we arrived Dick and Betty had the campsite lain out in a huge space around which we circled the wagons, with a fire pit in the center. On the road in, Dick had orange pie plates strategically placed to keep us zeroed in on the right track to camp.
We had a variety of "wagons" including pickups, vans, trailer, fifth wheels, motor homes and just plan tents. As each arrived at camp, they were duly signed in by Carl Holst of the Carmichael Gem & Mineral Society. Twenty-eight folks were from seven North Bay Field Trip Association clubs, eleven were from six Co-op (Central Valley) clubs and six were from the Beehive Rock & Gem Club of Utah. There were forty-five souls in all. The age of our rockhounds varied considerably, from six months to seventysix. It is likely not surprising that those younger than springtime had the tents, while us more mature rockhounds slept in greater comfort, commensurate with age and condition.
Dick Pankey was a tough, well-organized Wagonmaster. As each morning broke clear and sunny, at 7:45 AM sharp, a cowbell sounded the call to assembly, dressed or not. The orders of the day were read and a preview of the rocks we were to find were spread out on the card table for all to see and memorize. "You see one like that, pick it up!" Next, everyone signed the trip sheet so heads could be counted and rides arranged for those without adequate wheels. Finally, at 8:OOAM sharp (that cursed cowbell again) the vehicles lined up and were counted. It would be embarrassing to lose one. To avoid this, a tail gunner was assigned to follow, keeping in touch with Dick in the lead, by CB radio; to further assure that nobody got lost on a sidetrack or the deep washes.
We usually arrived at the morning's dig about 9:OOAM. Typically, the younger set scurried off with their picks, shovels and buckets, disappearing into the nearest foxhole left by their equally energetic predecessors. Although very few heads or bottoms were visible, you could tell that a hole was occupied by the steady plume of dirt and dust being discharged into the atmosphere. Also, typically, we more mature rockhounds, who would not stoop to such shenanigans, (or rather, could not stoop), wandered about the hilly slopes looking for float. Actually, this was quite a productive enterprise. The slopes, at a certain elevation were covered with much botryoidal agate float from what must have been very large geodes. With landmarks and compass bearing in mind, I made a mental note to a hot spot to prospect on the next trip to the area.
During the week, besides the world famous Hauser Beds, we visited places with such esoteric names as the Potato Patch, Straw Beds, Corn Field, the Big Windy and Gould Wash. A few broke away to go hard rock mining at Nancy Hill's Opal Hill Fire Agate Mine. Dennis Pigula showed off his rewards for brutally hard work at the mine face, in the form of material with lots of potential for quality fire agate.
One thing was abundantly clear. If you are willing to get into the trenches, work your picks and shovels and make the dirt fly, the Wiley's Well area still produces interesting specimens even after many decades of rockhounding. Yet, ecologically speaking, the terrain remains visually pleasing and has not been ravaged, as some would have you believe. The area west of Wiley's Well Road is still open to vehicular traffic, which made our collecting practical. However, the area immediately to the east of the road is classified as wilderness. Thus, with no vehicular travel possible, collecting is impractical in the Palo Verde Mountains where several previously popular collecting sites are located.
On our final day we collected petrified iron wood about 25 miles from camp, in Arizona at Gould Wash, which appeared to be a deeply scoured ancient drain to the Colorado River.
Around noon time, after a morning of collecting as the group slowly staggered up the steep rocky slope to where the vehicles were parked, it was apparent that Dick Pankey had hit the jackpot with many fine specimens. Being a generous guy, he offered to lead the gang back to the mother load. They were off like a shot over the steep walled washes. As I staggered to the second crest and peered way down in to the bonanza wash, the others looked like ants at a picnic! I decided that if I did find a nice piece of wood, I could never get both it and me back to the vehicle. Despairing of finding anything, I started the strenuous trek back to the Ford Explorer. Near the bottom of a deep rocky dry wash, I slipped and fell flat on my face. As I regained my composure, I realized that my left hand was resting on what turned out to be a 23-1/2 pound beautiful stump of a petrified ironwood bush! Getting it out over the next two deep dry washes, however, shall remain an untold story of sweat, struggle and pain. At least, the oldest rockhound got his prize. When asked how I found it, I modestly say, "oh, I just stumbled over it."
The next day we broke camp and one by one departed. I am sure there will be lasting memories of the thrill of the hunt, the potluck dinners, spectacular sunsets and conversations around the evening campfire. Especially, we know that all's well at Wiley's Well.
Mineralogy of the Jomac Mine San Juan County, Utah
by Patrick E. HaynesRock Pounder 10/98
(9the Place, 1998 AFMS Adult Article Contest)
(AUTHOR'S NOTE: this article is part of an unpublished paper. Sections on the geology and an the mineral descriptions have been omitted here.)
The Jomac Mine is the type locality for a recently approved uranium-carbonate mineral named blatonite Other secondary uranium minerals found at the mine are metazennerite, boltwoodite, coconinoite, uranopilite, and swamboito (the world's second location). A colorful suite of secondary copper minerals also occurs here, contributing to the variety of species from the mine. Now specimens will not be easily obtained a the mine has been reclaimed.
LOCATION: the Jomac Mine is located on Brown's Rim in the White Canyon mining district, San Juan County, Utah. Recent maps show that the mine lies entirely within the Glen Canyon National Recreation Area. Earlier maps, including the U.S. Geological Survey's 1952 15' Brown's Rim topographic map, showed a different boundary with the southernmost adits on lands administered by the Bureau of Land Management.
It is 3.5 miles east-north east of Hite and can be found in the west 1/2 of the SW 1/4 of section 31, Township 33 South, Range 15 East, at an altitude of 5,200'. Its three adits lie in the Shinarump couglomerate member of the Triassic Chinle Formation. Below the mine are the red sandstones of the Moencopi Formation. Above it are the sandstones and shales of the Chinle Climbing to the top of the hill above the mine, one has a nice view of Utah's canyon scenery, complete a with glimpses of the Colorado River below.
HISTORY: J.B. Blosser and A.M. McLeod located the Jomac Mine in November, 1950. Initially it was owned by the Ellihill Mining Company of White Canyon, Utah. Between May, 1951, and Jaanuary, 1954 nearly 300 tons of uranium and copper ore were shipped from the mine to the nearest ore-receiving plant at Mexican Hat, Utah. Two west-trending adits, 315' and 130' long. and 300' of additional workings had been driven into the deposit by August, 1953.
With financial assistance from the Defense Minerals Exploration Administration, 2,983.5' of exploratory drilling took plus between December, 1952, and June, 1953 (Trites, Jr. and Hadd, 1958). A south-treading adit, which does not connect with the other workings and is not mentioned in the literature, was noted by the author in 1988. Its length is about 75'.
Affiance Nuclear, Incorporated, from Spokane, Washington, had the mine from approximately 1954 to 1979 and Birco Development of Moab, Utah, from 1983 to 1985. Both companies now appear to be out of business, and their production is unknown. The Now Jersey Zinc Company owned the mill at Mexican Hat, but since it has been dismantled and reclaimed, the mill's records are probably lost.
The author first visited the mine in August, 1988, collecting a small amount of coconinoite. Visits in 1989 and 1990 were more productive, yielding about 70 flats of various secondary uranium and copper minerals. Blatonite was not noticed until July, 1989. Only about five flats vote collected, due to its scarcity and dangerous location.
The late Eugene Foord fiat realized the uniqueness of the mineral, and the research was continued by Michel Deliens. Blatonite was approved by the International Mineralogical Association in September. 1997, and is to be published in October, 1998.
In 1996 the author found large boulders across the seem road and the mine's three adits blocked by backfill. Personnel from Utah's Abandoned Mine Reclamation program had placed 'Do Not Disturb' markers in the fill. The adits had been closed and the road blocked on April 24, 1992. Seeding took place on November 1, 1992. The author has learned that beyond the backfill the adits have been blocked with concrete. If not for some close timing, mineralogy would be without the now mineral blatonite and without knowledge of the other unusual minerals from the Jomac base.
GEOLOGY.- the best account of the geology of the Jomac Mine is by Trites, Jr. and Hadd (1958) The present author has summarized some of their work in the following paragraphs:
Jomac Hill is composed of sedimentary rocks of continental origin and of Permian to late Triassic age. The rocks are on the west flank of the Monument uplift, a 60-mile long notth-tranding anticlinal structure. The beds have a general strike of N 25 degree W and dip 2 degrees SW. In places, reddish-brown siltstone of the Moescopi Formation underlies siltstone that can be traced into the beds of the lower part of the Chinle Formation. The Shinarump conglomerate intertongues with the lower past of the Chinle Formation and is present only on the east side of the Hill. (Trite: and Hadd). Each formation rests uncomformably upon the other.
Jomac Hill has intense faulting but little displacement in observed in the area of the mine. Slickeasided fracture surfaces on some of the samples collected at the mine indicate that minor post-mineralization movement did occur. As it the mine itself were not interesting enough, a reptile or amphibian track was found now the top of the Moencopi Formotion, just below the mine.
The White Canyon mining district lies within the Colorado plateau, a uranium-rich area spread over several states. Often on the plateau, in sediments of continental origin, the remains of organic matter are hosts for uranium replacement. The Jomac Mine is such a deposit.
MINERALS: the source of most of the Jomac Mine's radioactivity is from the Shinarump conglomerate's wood and sooty, black organic debris, both of which have often been replaced with uraninite. Secondary uranium minerals contribute to the radioactivity as well and are common throughout the conglomerate, mostly so the minerals coconinoite and metazeunesrte. Copper ore was also shipped from the deposit. With oxidation destroying a lot of the primary sulfides, the copper ore occurs mostly a secondary sulfate and carbonate minerals.
With the exception of coconinoite, most of the secondary minerals we associated with gypsum (variety: selenite) in layers, between bedding planes in siltstone, near the base of the conglomerate. These gypsum-associated secondary minerals occur only a micro-crystals. Most of the gypsum formed prior to the formation of the secondary minerals. It is not uncommon to find powdery white gypsum on small slicken-sided surfaces, indicating that minor movements occurred after the secondary mineralization and also indicating that there was some later precipitation of gypsum.
Trites Jr. and Hadd (1958) mention chalcanthite and goethite a occurring at the mine. The author has not observed chalcanthite, and it was probably misidentified carbonate-cyanoth richite or serpierite. Oxidation of the deposit is quite extensive and limonite is common, so goethite, although not observed by the author, is probably present. Trite. Jr. and Hadd also had two unknown yellow uranium secondary minerals which have since been identified as coconinoite and, most probably, boltwoodite.
There we two different assemblages of secondary minerals. A copper sulfate assemblage occurs just inside the southernmost adit. Associated minerals include copper carbonates, cuprite, sulfides, boltwoodite, and wetazennerite. A blatonite assemblage occurs at the erosscut's junction.. Associated minerals include malachite, smithsonite, swamboite, uranopilite, and minor mounts of serpierite and brockantite. The presence of asbolane is interesting and is likely responsible for anomalous amounts of cobalt and nickel found in minerals from both assemblages.
Unless mentioned otherwise most of the minerals have been reasonably identified with x-ray diffraction energy-dispersive analysis. A listing of the minerals which have been observed include alunite, anhydrite, asbolane, azurite, blatonite, boltwoodite, brochantite, cub onaic -cyanot nichite, chalcopyrite, coconinoite, cuprite, gypsum, hematite, jarosite, limonite, malachite, metazeunerite, pyrite, serpierite, smithsonite, sphalerite, swomboite, uraninite, uranopilite, and as unidentified orange-colored uranium sulfate or carbonate. The now mineral blatonite (UO2(CO3)H2O) occurs sparsely at the consent inside the mine. Found as yellow acicular crystals to 3 mm., it is closely associated with uranopilite and the fine-grained orange unknown material.
CONCLUSIONS: the Jomac Mine's three adits have been closed off and are inaccessible. As the adits are within the Glen Canyon National Recreational Area boundary, collecting mineral specimens there is forbidden. This is unfortunate as metazeunerite and coninoite can be found on the surface. Boltwoodite might be found in the basal gypsum layers at the southernmost adit.
There was not enough time to thoroughly investigate this unique location. The author has even thought to going through the obstacle of putting a mining claim on the location, putting up a reclamation bond, and so-opening the southernmost adits. However, that is probably not possible, due to its location, within the Glen Canyon Recreational Area. Also, collecting mineral specimens underground would still not be without its potential dangers. Re-opening the mine for a few rare minerals doe not appear to be worth the troubles one would encounter: physical, monetary, and bureaueratic.
ACKNOWLEDGMENTS: having relied heavily upon the work of Albert F. Trites, Jr., and George A. Hadd, I need to extend thanks for their having put together such a fine piece of work on the Jomac Mine.
I need to thank the late Eugene Foord for his research afforts.
Thanks to Michele Deliens for his work on
Thanks to Virgil Loath for allowing me the
use of the New Mexico Bureau of Mines and Mineral
Resources' microphotography equipment.
Thanks to Ted McDougall of the BLM's Monticello, Utah, office
and Roger Smith of the International Uranium (USA)
Corporation for helpful comments on the history of the
Jomac Mine and the White Canyon mining district.
Thanks to Dave Gillette. formerly of the Utah Division
of State History, for his comments on the reptile (7)
REFERENCES: Fleischer. M. and J.A. Mandarino. 1995. Glossery of Mineral Species. Tucson: The Mineralogical Record, Inc.
Thaden R.B., A. Trites, Jr., and T.L. Finnell. 1964. Geology and Ore Deposits of the White Canyon Area San Jaun & Garfield County, Utah U.S. Geological Survey Bulletin 1125.
Trites, A.F., Jr. and G.A. Hadd. 1958. Geology of the Jomac Mine, White Canyon Area, San Jaun County, Utah. U.S.Geological Survey Bulletin 1046 -H
Pleochroism and the Dichroscope
by Michael Kessler & Robert E. Sangers
From Bulletin of the New York Mineralogical Society 9/98
(10th Place, 1998 AFMS Adult Article Contest)
Due to the selective absorption of light along various crystallographic axes, some minerals will display different colors and hues when viewed through the dichroscope. This is pleochroism. When there is a play of color along two axes, it is dichroic; along three it is trichroic.
A dichroscope will display two colors or hues simultaneously, one via the incident light ray, the other along the refracted ray. If after viewing two different colors, the stone is rotated 360 degrees, a third color will be seen if the stone is trichroic. The two colors will appear because of the double refraction of calcite, so you will need to remember the subtle differences in color if the stone is trichroic.
This homemade dichroscope was passed along by a San Diego gem cutter, Dick Bunch. It is constructed with a piece of calcite at one end of a tapered tube. The calcite should be optical grade, without internal flaws, A convex lens (the magnifier) encloses the other end. The calcite end is blackened, usually with electrical tape, and a small square hole 2 to 5 mm placed in the center to allow light to pass through the stone in question and on into the scope. The thicker the calcite, the farther apart the squares appear. They should just touch, for optimal viewing. The calcite can be ground for a press fit in the tube. If too small, wrap in electrical tape until a tight fit is obtained.
With this instrument you should be able to observe the pleochroic properties of various minerals. A short list will follow at the end of this article. This technique is being used in Baja Norte, Baja Mexico to distinguish ruby corundum, garnet and spinet. Robert is running down a rumor of ruby in the Punta Prieta area of Baja, visa via, Juan Manuel Ariza Mendoza, a dry placer miner. who has sold rubies to a mineralogist from Los Angeles.
Here is a partial list of strongly pleochroic minerals:
- andalusite - brownish green and dark red to purple
- corundum - violet and orange
- spodumene - purple and colorless to pink
- apatite - blue and yellow
- benitoite - colorless and dark blue
- corundum - dark violet blue and light green blue
- zircon - medium blue and colorless to gray
- zoisite - blue purple and greenish yellow
Pink or Red
- andalusite - dark red and brownish green
- ruby corundum - purplish red and orange red
- quartz - brownish red and light pink
- topaz - light red and yellow
- tourmaline - dark red and light red
Some minerals are trichroic, such as red chrysoberyl (alexandrite), blue iolite, yellow topaz and brown axinite. For additional reference colors, we used The Handbook of Gem Identification, by Richard T. Hiddicoat, Jr.
Add a Bit of Salt to Our Collection
by Marvin Lundquist
From The Post Rock 6/98
(Honorable Mention, AFMS 1998 Adult A - Article Contest)
Woosh!, well, a bit of woosh at least, as we were lowered down the 1,000 feet to the lower level of the salt mine. The shoulder high, salt rusted, 8 x 8 steel box were riding in was crowded with the 11 rockhounds and 2 guides and boxes and bags. We'd been outfitted in a supply office for this trip to the lower depths by donning helmets, a belt with pockets to hold the carbon dioxide converter and the mining lamp batteries. Also eye glasses for those not wearing same.
For the minute and a half it took to reach the bottom, the view was of grey walls of concrete with an occasional air vent with wooden frames. The ride was easy and smooth. Our guide pointed out it used to take at least 4 minutes to make this trip. At the bottom the area was dimly lit but adequate to see the cut down van for our ride through the mile and a half of the main tunnel. We loaded up and were soon speeding down this 50 foot wide tunnel and 15 to 16 foot high walls of solid salt, and everybody turning on their own private flashlight to get a better look at the walls and boulders and chunks and pieces of salt (Halite) that lay at the bottom of the walls. The walls of salt were grey in color due to the "mud" impurities as the guide called it. The ceiling was a naturally occurring smooth break between layers. Very little flaking occurs from this ceiling our guide assured us. In fact he pointed out test picking in certain spots to see that it was safe. Occasionally we were met by a 4 wheeler coming from the opposite direction. This caused a bit of dust and it took only a lick of your lips to find that the dust was salty indeed.
The temperature was ideal and the riding just fine so one just looked. The guide said it took 2 1/2 hours for the air to be replaced in the mine. The lights of the vehicle we were riding in and from our flashlights flashed on the salt crystals on the walls. Most of the walls were straight up and down but some were caved in and some had slabs of salt parted from the wall ready to fall but the road way was wide enough that there was little danger of getting hit by failing salt. 45 to 50 sq. ft. pillars had been left to hold up the ceiling.
Some one asked if there was any red salt we could see. The guide obliged by calling to the driver to head for the muddy stuff in No. 1. The vehicle made some moves around pillars and heading in another direction and was passing more pillars, niches in the wall that contained working equipment from cats to transformers, more avenues, and by pillars that had numbers on them like 34 which we passed more than once.
We came to an area where we stopped and the guide checked to find our prize, lifted up a chuck and told us we could get out and find what we wanted. We in turn obliged him by doing just that willingly. I think everyone found something one size or another and one shade of red or another. We found this salt at the base of the walls, having learned that if we directed our light at the walls and at the top, we could find the reddish streaks that the scree was coming from.
We were on our way again and this time we stopped at their working center where there were tools, equipment, files--their underground headquarters. There was even a dug out chamber or niche that contained the porta potty. An item of interest to everybody here were the boxes of give-away samples. I lucked out and found a small chunk of clear salt crystal with a bubble. There was also a limited amount of red salt. They gave quite a bit of time here as this was our last stop, although I think we stopped on the way back to pick up some clear crystals. While wandering about, I found some delicate pink salt at the base of a wall. It was fragile but managed to capture a piece or two. We'd been given as much time as we wanted and as much salt as we thought we could handle at this stop. There was a bunch but we got up the shaft and on to the top and back into the sunshine. I overhear one of our group ask another what he was going to do with all his rocks and this gentlemen replied that he was going to put it under his bed and 20 years from now, I'll take them out and wonder what to do with them.
Someone asked the guide if anybody ever tried to scale the walls down there and he chuckled, 'only when a bunch of rockhounds come down here." Our rockhounds on this trip included Helen Dickson, Nancy Johnson and her niece, a Hadley from Missouri, Darlene Reck, the Nibargers, Cloughs, and the Lundquists. What a great and final chapter to the Ellinwood 25th Anniversary Swap. Thanks to the Lyons Salt Company, Lyons, KS.
*A note about the salt--the mineralogical name for the product coming from the mine is Halite. The salt here is not used for human consumption because of impurities but is used as an additive to cattle feed, for processing raw hides into leather goods, industrial water treatment, and as an aid in drilling oil and gas wells, but the big use is for roads and highways, particularly during the winter when demand requires an additional work shift.
*taken from a flyer from a neighboring mine in Kanopolis, which is of this same 250 to plus feet of salt formed during the Permian Age approx. 250,000,000 years ago when this part of the country was known as Pangeia.
by Doug Moore
From The Rockhound News 11/98
(Honorable Mention, 1998 AFMS Adult Article Contest)
Last week, my son John asked, "Didn't you say you had some radioactive rocks?" "Uh, ...yes," I replied hesitantly. He continued, "because my science teacher has a Geiger counter and we're studying nuclear physics this week. He told us to bring in stuff to test for radioactivity." "OK, Ill see if I can find them," I agreed, suddenly realizing how much searching it might take. My rock collection is an unorganized jumble that has occupied various basements, garages, and bomb shelters for 35 years, and currently resides in the dark confines of our back garage.
Surprisingly, the four specimens were quickly located. Two of them, uraninite and carnotite, were part of small, boxed collections my grandfather sent me from New York in the 1950's. The other two specimens, pitchblende in granite and "aconite," came from a Wisconsin prospector named George.
John brought the specimens to school, where the science teacher, Mr. Eisenhauer, ran a GeigerMuller counter over them. This instrument consists of a glass tube, filled with a dry gas at low pressure and polarized electrical contacts at the ends. When radioactive particles enter the tube, they produce an electrical discharge which is amplified into a click. The more and faster clicks, the greater the radioactivity.
The carnotite turned out to be the "hottest" of the four, giving off around 40 millirems per hour. Uraninite came in second, at 15 millirems per hour. Aconite and granite/pitchblende were barely radioactive.
All of these minerals contain uranium. Because the complex nuclei of uranium atoms are heavy and unstable, they're constantly giving off (emitting) particles in order to achieve a more stable state. Through this process, uranium "decays" into another element, which decays into another then another, etc. This cascade of disintegration finally stops when the stable atom of lead is reached. It takes uranium four and one-half billion years for half of a given quantity to decay.
Three types of radiation are emitted during this process. Alpha particles are nuclei of helium atoms, and are spent after they've gone through a few inches of air or hit a sheet of paper. Beta particles are electrons traveling at the speed of light, which have greater penetrating power than alpha particles. Gamma rays are similar to x-rays and can pass through a half-inch of lead without losing their intensity. Gamma rays are most responsible for creating an image on unexposed photographic film placed in close contact with radioactive materials. Most of the radiation emitted by my rocks is probably alpha and beta particles.
Uraninite (uranium oxide) is the primary ore of uranium. It commonly occurs as veins with a pitch like luster (pitchblende) associated with metalliferous ores of silver cobalt, nickel and copper. Or it may be found as grains or rare crystals in granite and pegmatite.
Uranium was discovered in 1789 by a German chemist, Martin Klaproth, in pitchblende from the silver mines at Joharingeorgenstade, Saxony. It was considered worthless, except as a ceramic coloring agent, until 1898, when Marie and Pierre Curie isolated radium from Bohemian pitchblende. But it takes 21,000 tons of uranium ore to yield one ounce of radium salt.
It wasn't until after World War II that uranium became the most sought-after material on earth. Hundreds of prospectors walked thousands of miles, exploring sandstone outcrops in valley bottom and high mesas of the Colorado Plateau, a 150,000-square-mile region in the Southwest. Bright yellow carnotite was the mineral they most often discovered. Carnotite is a secondary uranium mineral, formed by alternation and oxidation of uraninite. One of the distinguishing characteristics of secondary uranium minerals Is their bright colors, most often vivid yellows, oranges and greens. Only the copper minerals are as colorful. The uranium alteration minerals leave haloes of color in pegmatites and other host rocks. In the Colorado Plateau deposits, the host rock often contains abundant plant fossils. One giant petrifived log, on hundred feet long and four feet in diameter, yielded one hundred tons of uranium ore valued at $230,000 in the late 1950's.
One of the three richest uranium deposits in the world is the Erzgebirge region of Germany and the Czech Republic, where uranium was discovered and where the former USSR procured raw material for weapons. The others are the Shinkolobwe mine in Katanga, Congo, where prospectors came upon brilliantly colored rock fragments in 1915. Trenches were dug, revealing more fragments, until they reached bedrock containing uraninite veins. The ore body contains cobalt, copper, tungsten, gold and platinum. To date, the Shinkolobwe has produced more uranium than all other world deposits combined.
A third major deposit, called the "Eldorado," was discovered through aerial reconnaissance over Canada's Northwest Territories in 1930. Gilbert La Bine was flying over the eastern end of Great Bear Lake when he noticed bright colored outcrops on an island. More outcrops, plus silver and cobalt minerals were discoved on the mainland. Further exploration revealed five mineralized veigns containing abundant pitchblende and other ores. Each vein was several thousand feet long, and as much as 30 feet wide. Mining began at "Port Radium," first for native silver, and later for uraninite.
A host of uranium minerals, both primary and secondary, occur in many non-commercial deposits around the world. Their radioactivity, vivid color and (often) fluorescence are clues to their identity.
I'm positively "'glowing" with all of my new knowledge of uranium minerals. But for safety's sake, the four hot rock specimens that John borrowed were carefully labeled, and returned to the back garage.
Hurlburt, Cornelius S. 1967 Minerals and Man. Random House, NY.
Sinkankas, John. 1964. Mineralogy for Amateurs. Van Nostrand Co., Princeton, NJ.
Pough, Frederick H. 1976. A Field Guide to Rocks and Minerals.
by Clay Williams
From The Nugget 10/98
(Honorable Mention, 1998 AFMS Adult Article Contest)
Having donated a quantity of this mineral species to the Club, I feel obliged to say something in its behalf. The specimens are from La Paz County, Arizona.
Vanadinite is lead vanadate (vanadium oxide) chloride and is named for the vanadium in its composition. This metal is used in alloys where toughness is needed. An example would be chrome vanadium steel which, because of its toughness, has been used in armor plate.
It is a relatively rare mineral although this may not seem to be the case because of numerous occurrences throughout Arizona and New Mexico. However, none of these is (or has been) of economic importance: Even during WWII, when vanadium was in great demand, these localities were not mined.
The best examples to date come from Morocco. A few years ago, specimens from Milbladen, Morocco were quite common at shows.
The crystal shape is hexagonal; large crystals sometimes terminate in a pyramid (as with quartz), but more commonly the termination is truncated and stubby (as in beryl). The specimens I donated, although mostly the latter type, appear to have had trouble making up their minds. Crystals tend to be well-defined with smooth faces, and sharp edges; this species is seldom found in massive form.
It is a secondary mineral, found within oxidized lead ore deposits enriched with vanadium. Associated secondary minerals include wulfenite, descloizite (also a vanadate), mimetite, quartz & limonite.
An unfortunate property is a very slight photosensitivity to light: The observable result is a gradual darkening/dulling. This may take years and varies from specimen to specimen. In any case, when exposed to light, change will eventually be observed and this makes it a poor candidate to be used in jewelry. Note that when vanadinite is stored in darkness, there seems to be no change in color.
Speaking of color, it is often vivid red. Other shades are brownish, brownish-yellow and yellow. The La Paz County locality material is typically an intense red, but occasionally grades into orange-red and lemon-yellow.
Sinkankas, John. Mineralogy for Amateurs. NY: Van Nostrand Reinhold Co, 1964.
Fleischer, Mandarino. Glossary of Mineral Species. Tucson: Mineralogical Rec. 1995.
Anthony, Williams, Bideaux, Grant. Mineralogy of Arizona. Tucson: U of AZ, 1995.
More of the Rays of Big Brook
by Robert Dann & Sylvia Seda Pucci
Part of this article is copyrighted.
by Terry Vasseur
From The Rockatier 11/98
(Honorable Mention, 1998 AFMS Adult Article Contest)
We arrived in Lake George, Colorado on a late Sunday afternoon in early September, apprehensive and unsure of just where the mine was located, whether or not it was still open. and what the camping facilities were like. We found Lake George. an unincorporated city with a half dozen buildings built around a crossroads. quiet and without much outward activity. A roadhouse advertising steaks seemed to be doing well enough with five or six cars parked outside, but not much else seemed to be going on. I briefly savored the image of a thick, juicy, Midwestern sirloin steak with all the trimmings, then shook off the thought, turned around, and headed west in the direction we had traveled, this time being careful not to miss the road leading to the mine. It had rained on and off during the afternoon at the higher elevations, and I wanted to make camp before dark while the weather held.
Two miles out, amid road construction barriers off to the right, we saw a sign that read "Tarryall Detour". This was our turnoff all right, but just what the detour business was all about was a little unsettling. I proceeded cautiously onto the fresh gravel roadbed until I saw the signs I was looking for, "Topaz Mine" and another advertising the "Stage Stop Campground". The gravel road construction eventually ended, leaving a worn, potholed, two-lane blacktop. Once again, two or three miles further, we were reassured by a couple of signs that told us what we were seeking was still ahead. We passed a number of picturesque ranches along the way that appeared to be for permanent, year-round living and tried to imagine the fierce winters here at nine thousand feet. At last, we reached our final turnoff. After another mile or so we again turned to the right and climbed the side of a hill, arriving at the campground.
A small building with a prominent, glowing red Coke machine standing near the entrance greeted us with a sign proclaiming itself to be the office. I stepped out and panned the pine shrouded horizon. There were two RV campers. one further up the hillside and the other near the office. At least we weren't alone! Through the office window I saw someone in a straw hat, whom I later learned was Walt Rubeck, the mine operator. He was talking on an old time candlestick telephone. not a replica, but the Real McCoy. From the conversation I overheard while siging in, Walt's dog had apparently been stung in the eye by a bee and he was consulting with a veterinarian somewhere about the treatment.
We picked a campsite overlooking the office and away from the other campers, then proceeded to set up our tent. The tent stakes, much to my surprise, went easily into the ground I'm more accustomed to the hard packed, rocky terrain found in most western desert campsites where tent stakes aren't so easily hammered into the ground. The entire hillside here appeared to consist of salmon colored granite boulders surrounded by decomposed gravel of the same. The whole area, from what I had read, is part of a huge, pink, Pike's Peak granite batholith with numerous pegmatite formations throughout. That fact was made evident to me the next morning when I found, near the campsite, a beautiful, clear, quartz crystal point glistening in the sun.
Once the fire was going and foil-wrapped potatoes placed on the coals, we (my wife Tessie and I) were off to experience those hot showers that had sold me on this remote campground (not to mention its close proximity to the mine). Along the path leading to the showers, marking the path's perimeter, were large specimens someone must have collected the nearby mountains. I recognized black tourmaline crystals in matrix, smoky quartz, pink quartz, amazonite, blue/green copper stained minerals, and muscovite (mica) books two inches thick! Somewhere around here there had to be good collecting sites. The hot showers, although rustic, were adequate as were the indoor flush privies. Both were welcomed by us weary travelers.
After dinner, by camp light on the campsite table provided, I collected my thoughts on the day's events. The
omnipresent silence on the mountain top was briefly broken by choruses of coyotes calling and answering one another
from at least three separate but nearby locations. Once, a whooshing sound of wind passing through stands of pines
on a ridge close by, that seemed to last for minutes, culminated in a brief but gusty blast of wind through the camp. I
feared we were going to be blown off the mountain, but as quickly as it arose, it dissipated and once again there was
only silence and darkness.
The next morning after showers and coffee, we packed up, walked the dog, and were off in search of the Tarryall Topaz mine. It was a short two miles further up a narrow dirt road, a right turn at Matukat Road, and there we were at the end of a rather pleasant, pastoral alpine canyon. Wookie, our nine-year-old, well-traveled Chinese Shar Pei, protested having to remain in the car - no dogs allowed!
We approached the mine, where a man and a woman were working a kind of dry washer contraption that we later learned was designed by Walt to separate the gem bearing gravel into two categories by size. They told me the screening process used to be done by hand before Walt built the mechanical separator. It appeared to work well enough, easily handling earth and gravel as fast as a man could shovel it in. The apparatus was powered by an electric motor; the power source for which, either generator or power line. I didn't determine. The screens were held in place with "C" clamps. I suspect this allows for adjustments in grading size or easier replacement of the worn screens. Rocks larger than an inch and a half were directed to the discard pile (discarded after inspection for any monster topaz crystals, I assumed!). What remained was a pile of the premium coarse gravel and another of the finer grade, presumably containing stones less than a couple of carats. Walt, wearing his straw hat, was seated on a tractor fitted with a front end loader. He was busy ferrying scoops of earth out of the mine for screening and returning the processed discards. From what I could see, it looked like a fairly efficient operation; about what you would expect from a mining venture that's been in operation for almost ten years.
We were immediately approached by the woman (whose name I failed to get), inquiring what our 'intentions
were. I responded and was told there were two options available to us: (1) we could screen on site, two five gallon buckets of premium grade gravel for $60 plus a cutting contract. (Walt would facet a three-carat minimum stone from at least one of the topaz crystals we found for an additional fee, depending on the size of the cuts stone.); or (2) we could carry out $ 10 buckets which generally contained small specimens only. The best way to describe our reaction was sticker shock. I was thinking $50 worth of gravel and maybe coming out with one or two stones suitable for faceting some day. A quick decision was needed. I chose number (1), the good stuff, reasoning we would probably never have this opportunity again. Besides, I didn't relish the idea of driving down the mountain overloaded with sixty-pound buckets of gravel!
The gravel buckets arrived under the screening tent. We were instructed in the proper screening technique, which consisted of putting a shovel or two of gravel on a heavy gauge screen and then spraying water over it as we washed it by hand, using a circular motion. Thick rubber gloves were provided because considerable force is required to remove the sticky sand and clay. Topaz was readily distinguishable, clear and lustrous. An occasional piece of dull, highly fractured quartz was encountered but never mistaken for topaz. Nice pieces of smoky quartz were sometimes found, we were told, but to my dismay did not appear in our two buckets. This was clearly a team effort, I screened and sprayed, and Tessie shoveled and held the little baggy containing the treasures we found.
Walt checked our progress periodically. He seemed genuinely interested in what the gravel was yielding. When the two buckets were completely processed, we had nine 10 to 5 0 carat, Tarryall Topaz crystals, which was about average for two buckets, we were told. We had a blue, a sherry, some clear, and a couple that exhibited bicolor effects. Most were highly included and fractured.,
Walt Rubeck, former building foundation contractor, now self taught gem stone prospector and topaz cutter, met me at a table set in the open which served as his office. He walked with a pronounced stoop, which I assumed was the result of years of bent over prospecting. I, too, felt a little pain in my back just from hoisting my two buckets and emptying the processed screens (not to mention driving ten hours the previous day). Back problems were apparently an occupational hazard of small scale mining and long haul truckers.
Walt proceeded to evaluate the topaz we found. While we waited, I was reminded of an image I had seen somewhere of the Wells Fargo Paymaster disbursing the payroll to the miners, only in this case, I was about to do the disbursing. There was a surreal feel about the moment, me sitting at a wooden table in the open with a grizzled old miner in the shadow of the timeless Rocky Mountains. I had an uncanny feeling of being taken back in time to the heydays of the Pike's Peak gold rush.
Walt quickly dismissed all but two stones. recommending I have him cut both. The smaller stone was an aquamarine blue from which he estimated he could cut a five and a half carat Lone Star cut. This was my choice, too. The larger was a water clear tip of a crystal one inch in diameter. It would cut a larger stone, for sure. but lacked the appeal of color. I settled on the blue. At $185 cutting cost, the other stone could wait until and if I learned to facet. Walt sniffed about how he hated to see cut-able stones leave the mine because it was the stones that were properly cut and set that were his primary advertising. I couldn't help but get the feeling that, although I had interrupted Walt's mining activities, he was equally content with mining me!
With business concluded, I asked Walt to see an example of the mine's famous topaz with Phenakite (Beryllium silicate) inclusions. Walt coyly asked me if I was buying. I sheepishly answered no. He went to the trunk of his car, anyway, and produced a pasteboard box with specimens that he had polished the faces of in order to better view the unique inclusions sometimes found in Tarryall Topaz. He shuffled around in the box until he found the right specimen then handed it to me along with his loupe. Inside the clear topaz I saw a small hexagonal crystal of Phenakite. Out of curiosity, I asked Walt how much he wanted for it. I followed his eyes down to the table, where the package was marked $3,000.
With show and tell over, Walt went back to his tractor and I returned to my car to check on the dog and retrieve my video camera. Walt had given me permission to film the mine. I needed to take care of that quickly if we were to stay on our trip plan schedule, which meant getting back on the road by eleven o'clock. It was a long way to Cheyenne.
I walked down to the mine and noted how unremarkable it appeared. It looked much like an ordinary gravel pit at the base of a large ridge. There was quite a number of large boulders that Walt was going to have to move n order to continue his excavations. At their current rate of working the claim the lady had boasted, "Me mine could operate for another hundred years." Maybe so. I remember Walt saying when he was trying to convince me to let him cut the second stone that this was going to be the last year the public would be able to purchase buckets of premium ore, something about this being the '90's. I wasn't quite sure what he meant by that. All I knew for sure was, this was probably the one and only time I was going to purchase buckets of ore here at the Tarryall Topaz mine regardless of the bucket price or the number of years it remains in operations. It had been a long drive from California, and I don't know when I will be passing this way again.
Then again, who knows? Maybe when I get my faceted, blue Tarryall Topaz in December, I'll change my mind.
More About Polishing
by Okley Davis
From The Rock Rattler 12/98
(Honorable Mention, 1998 AFMS Adult Article Contest)
The brilliant super shine (polish on many lapidary stones is often elusive if not seem ugly impossible to attain. Frequently, despite all your efforts the finish is dull and unattractive. Dealer displays of the same rnaterial indicate you are doing something wrong.
There is no one polishing technique nor any one polishing compound that will work for all stones. A few of the more common polishes are diamond, rapid 61, chrome oxide, cerium oxide, aluminum oxide, etc. All are relatively expensive: some will work on certain stones, but not on others. Some will work, in a tumbler, others only on a spinning wheel, leather pad, or muslin buff. If you are going to work a wide variety of stones, you will have to use a variety of polishes and differing techniques. The polish I find that works on many stones is the Fitzcorp (one of the demo dealers at our last show) Final Polish Alumina. It is also about the least expensive. The last price I have is $12.50 per pound. Though the technique differs for wheel and tumble polishing, the same polish can be used for both. Generally speaking, most wheel type polishes will not work in a tumbler.
Wheel polish or tumble polish? Which is best? Normally I prefer wheel polishing for the technical challenge and the satisfaction of a job well done, and the magic of a brilliantly shining stone appearing before your eyes. Also, remember if you plan to show your products in competition, they must be hand finished. If you plan to sell your products, tumbling is the best bet. The finished product is apt to be produced faster, more uniform, and sometimes has a superior finish. Sometimes I am not satisfied with my best attempts for the desired finish with wheel polishing and will then try a follow-up tumble polish. As an example, obsidian seems to polish best, with the right technique to avoid chipping, in a tumbler. The tumbler I use is the vibratory type.
The stone you plan to polish must be properly prepared and squeaky clean. The most important step is the one you have just finished. No amount of rough sanding will eliminate that flat spot you left on the stone following the grinding and shaping. No reasonable amount of fine sanding will eliminate noticeable scratches not removed in the rough-sanding phase. You cannot poilish a stone that has not been sanded properly: a sanded stone should appear finished and may have a semi-dull finish. Cleaning the stone, the dop, and your hands between each polish step is critical - otherwise the finish may be dull. If you discover any problem (flat spots, scratches, etc.), go back to the previous step(s) before proceeding further. A lot of work? Yes, but unavoidable.
You can completely finish your cabs in a tumbler after shaping and grinding on a wheel, but I primarily use the tumbler for polish only. The technique is relatively simple. Certain variations may be required for your particular tumbler. Fill the tumbler to the proper level with ground corncobs. Add 1 oz. of Fitz Final Polish Alumina per each 5 pounds of tumbler capacity. Add a few squirts of penetrating oil to help bond the polish to the corncobs. Check polishes daily and add a few more squirts of the penetrating oil each day. It may take up to 3 days to achieve the best possible finish.
WHEEL POLISHING. I have pre-polished the stone on a 14000 grit diamond impregnated belt and cleaned the stone, dop, and my hands with dishwashing detergent and running water. The Fitz final polish will be applied on a leather belt using considerable pressure. The polish mix will be the Fitz polish mixed with an approximately equal amount of liquid dishwashing detergent. If the mix is too thick, it may clog the leather belt. Add a small amount of water. Following this polish, clean up the stone, dop, and your hands again and polish the stone with Zam on a muslin belt and finally on a dry muslin belt. Still not satisfied with the polish? Then you could try a follow-up tumbler polish.
by John Dickson
From Rocket City Rocks & Gems 5/98
(Honorable Mention, 1998 AFMS Adult Article Contest)
Bauxite is a rock, i.e.: it doesn't have sufficient consistency in its chemical composition to qualify as a mineral. It is a hydrated aluminum oxide1 and rarely found in distinct crystals. When so found. the crystals. monoclinic gibbsite [Al(OH)], orthorhombic bochmite [AlO(OH)], and orthorhombic diaspore [AlO(OH)]2 and various amorphous forms occur in earthy, clayey, or pisolitic (spherical or subspherical grained) masses colored white or yellowish (when pure) or brown to reddish (when containing impurities such as iron oxide or bitumen)3.
So, who cares'? Well, bauxite is the primary ore from which we obtain aluminum. Now, a great percentage of the earth's crust contains aluminum; however, it is mostly combined with silicates. You will notice that the chemical formulae for bauxite do not show any silicon. It turns out that it is very difficult to separate aluminum from rock containing silicates and carbonates, whereas, it is considerably easier to perform this operation when the aluminum is found as an oxide, without the silicon (or carbonate) compounds.
Before a practical means was discovered for separating aluminum from bauxite. the metal was very rare. Prior to the 1880s, aluminum was more precious than gold. Although aluminum ores are plentiful, the metal is tightly bound to oxygen. and no cheap means had been found to free it. Consequently, the Washington Monument is capped with a small pyramid of aluminum: The Danish King Christian X wore a crown of aluminum; and at dinner parties of Napoleon III, plates of gold were placed before ordinary guests, and an aluminum plate before the guest of honor4.
Bauxite is found in residual sedimentary materials after the dissolution of carbonate and silicate rocks5 (mostly in subtropical areas). It does occur in Alabama, Arkansas, Georgia, and Wyoming6, Surinam, Jamaica, Ghana, Indonesia. and many other places. Note that the preponderance of the substance is found where the climate is damp and hot (Alabama sure fits that description in my opinion). How Wyoming got into the picture is a mystery to me (as are many, many other things).
Special names are given to the sedimentary and metamorphic rock mineral assemblages including the mineral aluminum. Eclogite is the
name given to a rock of basaltic composition but whose mineralogy significantly differs from basalt, in that it contains sodium and aluminum ill important quantities7.
The first commercially practical extraction process for Aluminum was developed in 1886 by Charles Hall in the USA and (separately) by Paul Heroult in France8. The process involved passing an electrical current through a molten cryolite bath9 (using enormous amounts of electricity10). Cryolite is a fluoride of sodium and aluminum and is still used in synthetic form as a medium in which to melt aluminum oxide, from bauxite form. subsequent to aluminum separation by the electrolytic process. Of direct interest to the rockhound is that aluminum oxide is the basic compound used as a primary abrasive in the lapidary.
Should you be lucky enough (as I was while in Thailand in 196811). you may find aluminum oxide (with various impurities) in the form of very special crystals. These are generally known as rubies, star rubies, sapphires, and star sapphires; all various crystal forms of corundum.
1 Guidc to Rocks and Minerals, Mottana, Crespi, and Liborio, Simon &
Schuster Inc., New York, 1978, p83
4 The Flight from Science and Reason, edited by Gross, Levitt, and
Lewis, The New York Academy of Sciences, NY, distributed by The
Johns Hopkins University Press. 1996, p25
5 Op cit, Guide to Rocks and Minerals. p83
6 Rocks At Minerals edited by A F 1, Deeson Clarkson N. Potter Inc.,
New York, 1973, p67
7 A Color Atlas of Rocks and Minerals in Thin Section, MacKenzie and
Adams, John Wiley & Sons, New York, 1996, p 154
8 Rocks & Minerals Richard M. Pearl, Barnes and Noble, New York,
9 op. cit. Guide to Rocks and Minerals p83
10 op. cit. Rocks & Minerals, p 194
11 Field trips during R&R; periods while serving with the US Air Force at
Takhli RTAFB, Tailand
Learning to Use It or Lose It
by Dick Rantz
From Rockhound Special 10/98
(Honorable Mention, 1998 AFMS Adult Article Contest)
LEARNING TO "USE IT OR LOSE IT"
Population growth and social change are the two main driving forces that make it necessary for us to reexamine the way we've been doing things up to now. These are two "BIG GORILLAS" that none of us can do much about. But if we don't understand them and adjust to them, they could put us "out of business" in a hurry. However, if we make timely adjustments, hopefully we can keep our clubs and organizations in business and have lots of good rockhounding hobby opportunities left for ourselves and our grandkids to enjoy well into the new century. It won't be easy and "Business As Usual" just won't hack it; but surely we should try and give it "our best shot".
First, here are a few facts about population growth. Back when our hobby really got going after World War II, the US population in 1950 was about 150 million and our Northwest Federation region only had a little over 4 million inhabitants. By 1980 it had grown to over 226 million, with almost 9 million in our region. Year two thousand projections forsee a US population of over 275 million, with about 12 million in our area, and by 2030 (just a little over 31 years from now!) we can expect around about 375 million for the US and 18 million folks hereabout. Wow, is that a "GORILLA", or what?
Social change sort of sneaks up on us when we aren't looking. Who would have expected that we would see over 39 percent of families with both adults holding full time jobs these days, compared to only 17 percent in 1969? And now there's "Monday Night Football", and all the other "must sees" on TV, and a whole new set of outdoor (and indoor) activities that have become popular, like "ORVing", dirt biking, "Ski-doing" and so on. Next up and coming on strong is the "New World" of the computer, with E Mail and the Internet using up more and more of our ever shrinking reservoir of time available for recreational activities. All this adds up to the other, still growing, "BIG GORILLA" of social change that we have to deal with if we are to keep our hobby "alive and well".
The flip side of all this also has to be taken into account. There are positives" to consider and exploit. We're not "dead yet"! As long as we humans continue to crave adornments and fancy baubles (as we have for over 20 thousand years!); as long as almost every little kid loves to collect rocks and as long as there's joy in crafting something with our own hands, there will always be a niche for those of us they call Rockhounds.
So, its look at it this way, the positive side of more and more population
means that there's that many more folks to be interested in coming to our show
and admiring and acquiring our wares, and possibly being attracted to our hobby.
It's not so much our FUNCTION that's in jeopardy as it is our perhaps outdated
methods and our "marketing". Here the computer with it's E Mail and Internet
capabilities may well prove to provide the "Magic Bullets" with which we can
seek to overcome, if not "kill" our two "BIG GORILLAS". We're not there yet,
but it's coming fast. Already, over one third of all households have at least
one computer, and in another few years it will be two thirds. Then we'll be
able to have and use our club and Federation websites to advertise our shows,
provide information about our field trips and - "coming events" serve as the
marketplace of RECYCLING our surpluses, and myriad other purposes. Also
we'll be able to reorganize the way we do our and conduct our program
and streamline our management methods. Just as in the world of business today
E Mail and networking will soon permit our club and federation officers and directors to conduct all sorts of business virtually anytime; instead of having travel and meet infrequently, at considerable expense in time, money and effort. Perhaps we can even finally achieve a little "Political Clout" at last, with direct E Mail channels to our representatives and other Government officials. These are just a few of the OPPORTUNITIES in the Century just ahead
TAKING A STEP FORWARD
TAKING A STEP FORWARD
Crucially important if our hobby is to both survive and prosper in the new century, will be our wise use of the natural resources that we inherit, and that we wish to leave as inheritance to those who follow. Above all, we need to adopt for ourselves and teach to all the principles of conservation and full utilization that we dub as "RECYCLING". Perhaps the most effective and long lasting way to do that would be to amend and add to the AFMS Code of E Ethics. It has long provided the one set of guidelines that every Rockhound. is constantly made aware of and which is respected by (nearly) all. Our suggestion is the following the present "code" statement: "I will cause no damage to collecting materials and will take home only what I can reasonably use", we ADD a new item to address our feelings about conservation, full utilization and recycling. Accordingly, the following is proposed:
I WILL PRACTICE CONSERVATION AND UNDERTAKE TO UTILIZE FULLY AND WELL THE MATERIALS I HAVE COLLECTED AND WILL RECYCLE MY SURPLUS FOR THE PLEASURE AND BENEFIT OF OTHERS.
A Hunting We Will Go
by Mary Jane Boutwell
From Rocky Echoes 2/98
(Honorable Mention, 1998 AFMS Adult Article Contest)
After a week of "Is it going to rain?" or "Will it be dry enough?" I was ready for an adventure.
Michael Williams, one of the more recent members to join the MG&MS.; had reported a location where he had found
fossils and crystals of gypsum variety selenite - both in numbers large enough to find easily.
During the first meeting of the fossil special interest group, members agreed to combine both the mineral and fossil groups into a larg, though still small group, to try this site. Hopefully. this group would make a good impression and there would be a regular Society field trip later.
On the day of the scheduled trip, 5:23 a.m. found me up and making coffee for the thermos. By 6:00 a.m., Mary
Folsom was loading her gear into my van. My plans were to get to the site, pick for a while, eat lunch and be home by 2:30 p.m. and doing lots of thin-as around the house. We were in high spirits as we roiled along. Remembering our last trip together, Wildacres in September 97, really kicked in the feeling of "This is going to be a great day."
The first to arrive at the central meeting place, Mary and I entered to find a window to watch incoming traffic. Just as breakfast was ordered. Michael;s father dropped him off and he came inside to join us for a meal.
Shirley Randle was the next to arrive with her breakfast in a well-known brown bag. While we were eating, Betty James and Janie Hand joined us. You could not get me to say whether it was time for all the other customers to get on with their day or if we just took over the place. But as we walked out the door, there were only three or four customers left and the happy, loud sounds vanished
As Michael was riding in my vehicle, we took the lead. The first thing we did was miss the first turn. That set the tone for the rest of the journey. Michael had made the trip once before. We were guided on this trip by the memory of his previous trip, including repeating all the wrong turns from that remembered trip, the oral directions, and a bad tourist map of Mississippi. Although the map had few if any county roads marked, most of our trip was to be on these unmarked county roads.
One of the highlights of the morning's travel was a well posted "T" intersection. It told us how to
get anywhere and everywhere - Pachuta to Dollywood to Moscow by way of Paris, France. It did not
tell us how to get to Shubuta, which was our destination of intent.
By now, everything was hilarious. We stopped in downtown Shubuta. Yes, there really is such a place and we really did find it. The only question would be about the downtown part. We found the correct road, crossed the river and missed the driveway. Even with all of this, it took us only about two hours to make the trip.
We were given permission to park in the side yard. At this point everyone was ready to put on old shoes, old clothes, and pick up the essential something to carry the finds of selenite and fossils back to the vehicles.
We followed the path past the garbage pile, and on to the Red Bluff outcrop where tar down below we could see the banks of the Chickasawhay River. For those of us from the flat lands or slightly rolling hills around the Big Black River, this was a tall step for several tall Indians. We followed along the edge of the bluff, keeping far enough back so as not to cave away an unstable area. The several trees Michael pointed out as having fallen since he had recently been there did not reassure anyone.
From this point on. Michael, being the only male and young enough to move easily, really did double duty. He scouted ways for us to get down to the areas where the pickings were rich. He got all of us down the almost vertical banks, at least sixty feet of hard climbing in thick, heavy clay mud, as slick as goose grease in places and sucking and pulling you into its depths in others, but he still found time to find and identify fossils. There were large chunks of gypsum variety selenite, clams, sea shells,
coral and others we hope to identify at the next meeting of the fossil group.
Back to our adventures. Our first venture down to the first bench was tantalizing. Michael kept saying the fossils are better 'down there' or 'over there.' So we climbed back out and found a nice (but wet) log for all of us to sit on as we snacked. The five ladies reminded me of turtles sunning on a log. You could see we were hunkered down planning to stay. The only problem with that was we could see down to the next bench - the one Michael was aching to get to. He knew there were clam shells here. He wanted a larger one for his competitive exhibit.
We alternately practiced being mountain goats and walking on water from here until we returned to the top of the bank. None of us have perfected either skill, but we did manage with shoes a large as snowshoes to get into an excellent fossil ground. It was around this time we picked up the name "mudbabies."
Some of the identified finds of the day were gypsum variety selenite. Several were double terminated crystals and a couple of twinned crystals all of which will probably go into exhibits, Fossils found and field identified were Nemocardium diversum, Spondylus dumosus, Pecten byramensis, Mambrimia brevidentata, Dentalium mississippiensa, Archonhelia vicksburgensis. Balanophyllia elongatta, Chione craspedonza. Also found was one shark tooth, Odontaspis. The fossils listed above are bivalves, gastropods, and corals.
When we had had all the fun we could stand for the day, everyone slowly made their way back to where our last drop off had taken place. Half of the equipment had been left there for a return pick up. As we tacked back and forth up the Rocky Mountains, everyone commented on how much heaver everything had become. By the time we got to the top, several items had been high graded. I was in the lead did not want anyone to know I had picked up anything that was not perfect, so pride insisted I carry everything out
On the way home we reversed our trip south. We got lost, then found our way several times, and came home. That night as I tried to sleep, my body told my pride that pride causes an aching body and may cause a fall.
by Doris Cullom
From Carny Hound 4/98
(Honorable Mention, 1998 AFMS Adult Article Contest)
It was in September of 1970. The locale: Maury Mountain, southeast of Prineville, Oregon. The goal: The famous Maury Mountain Moss Agate. The cast: My sister Eileen, and her husband Mac - in their car and travel trailer; and our Mom Nellie and I - with me pulling our travel trailer with my trusty old '62 International stick-shift crew-cab truck, loaded with camping and rockhunting gear. (I was brave in those days.)
We unhitched the trailers and camped in a park near Prineville. The next morning the four of us got in the truck and headed out. I inched the truck up the rough dirt road to the digging area at the top of the hill, where we noticed a few other rockhounds wandering aimlessly around.
We all piled out, and started looking around - checking out the abandoned holes left by our predecessors, but the more we looked, the more disappointed we became. Not a chip did we find, and the holes, all located in the digging area on the lower side of the road, looked like nothing but gosh-awful hard rock mining.
Mac and Eileen finally opted to crawl down in one of them and start chipping away. Mom wandered around amongst the sparse sagebrush in the virgin territory on the upper side of the road, while I knicked a few rocks along the edge of the road, and told her I'd meander ahead a ways to see if I could find anything.
Suddenly she stopped and said firmly, "Well, I'm gonna dig right here!" and plunged her shovel down in a mound of loose dirt kicked up by a gopher. "Well", I thought, "if she wants to spend her time digging gopher holes, it's OK by me - everyone to his own choice", though it was perfectly obvious that all of the digging was below the road.
I took a few steps she took a few shovel loads - then hissed, "Doris, come here! I think I've found something!" I thought, "Yeah - probably a sagebrush root or", I giggled, "maybe a petrified gopher". But I sauntered over to give her a hand.
By golly, she DID seem to be hitting something. My curiosity whetted, I fell to with my shovel, and in a moment, my heart gave a lurch as my shovel hit something that reverberated with that unmistakable "ding" so dear to a rockhound's ears. We looked at each other, scraped away a spot with our hands, gave it the old spit test - and there it was, beautiful, lovely red moss agate.
Mom said excitedly, "Go get Mac and Eileen to help us!" I scurried over to their hole and tried to quietly pass the news. They crawled out, showing little optimism, but willing to humor us. They perked up considerably when they got down on their knees to take a good look.
Well, the action really started to commence with dirt and rocks flying every which way from four shovels. The more we dug, the bigger the piece got. Did you ever try to dig unobtrusively so as to not advertise your find? Can't be done.
We soon had all the rockhounds gathered around us, muttering, "But nobody EVER digs up here on this side" while Nellie just grinned from ear to ear. We dug - the sweat poured, we dug some more, back to the truck for some pry bars and picks - back to the truck for the really BIG pry bar - we dug and pried out chunks until we were exhausted. (I don't recall that we even took time for a sandwich).
We finally gave up, and I backed the truck up to our beautiful, huge pieces of moss agate. Willing and eager hands helped us load our loot (eager for us to get the heck out of there so they could take over!)
I low-geared the truck down the hill (with it's tail a-draggin') and all the way back to camp we had to listen to Nellie chortling " Boy, oh boy - if you want to find agate, just call on me!" interspersed with, "I'm the Queen Bee around here - no cooking, no dishwashing I'll take my breakfast in bed"---and on and on ad nauseum, while we meekly had to agree. "Yes, Nellie, you're the head agate hunter around here".
Mom delighted in telling her gopher mound - moss agate story to anyone who would listen and look at our (no, make that "her") beautiful specimens. Since she's now up there rockhounding with the angels, I'm delighted to pass her story on to you.
Snowbird Mine Field Trip
by Ruel Janson
From Hellgate Breezes 9/98
(Honorable Mention, AFMS Adult Article Contest)
The Snowbird Mine field trip on Aug 8, 1998 was attended by 21 club members, guests and Speacks, the dog. On the way up to the Surveyor Creek road we were halted for a while by two school buses full of Native American fire fighters who were trying to find two small fires in the area. They finally pulled off on a side road so we could pass. We never did see any smoke in that area, but on the way back we could see smoke on the top of a mountain several miles to the north.
It was a warm sunny day and the shade felt good, when we could find any. The air was clear and the scenery superb. Wild flowers were just passing the peak of blooming. Everyone found interesting rocks and minerals to add to their collection or beautify their yards. The Forest Service loaned Reuel the key to the gate so we were able to drive right to the mine after removing a few fallen trees, snags and rocks from the road. Thus people were able to take larger rocks than if they had to carry them out.
There is a big variety of minerals there to choose from, including quartz, calcite, parisite, fluorite, gersdorffite and many more. The mine was worked for the fluorite which is used as a flux for making steel and opalescent glass, enameling cooking utensils and preparing hydrofluoric acid. The fluorite occues in two colors, light green and dark purple. In combination with calcite and quartz it makes some attractive specimens.
Vugs in the massive quartz and calcite contain quartz crystals, but these have been pretty well worked out by collectors. We found a few crystals by digging in loose mounds of dirt, looking on the ground or scraping out some overlooked vugs.
On the way out, some of us went down Fish Creek to Interstate 90 and saw the largest Ponderosa Pine in Montana. It is 350 years old and still growing.
This was an interesting trip and I think everyone had a good time.