Agate, a translucent cryptocrystalline variety of quartz, is one of Natures most
beautiful gemstones. For thousands of years man has prized agate for personal adornment,
for this variegated chalcedony is characterised by oft-contrasting colours that may be
arranged in either strongly contrasting bands, irregular swathes of colour, or moss-like
Some 3,000 years ago the ancient Egyptians sought colourful agates and other
chalcedonies from the Aghates River (now called the Drillo River) in Sicily. As a
consequence, many agate artefacts and jewellery have been found in the tombs of long dead
Kings and Queens of ancient Egypt.
Today, agate is still very much in demand, for it is a uniquely patterned gem material
that offers its owner the desirable attributes of beauty and durability.
Agate Creek in far North Queensland is the acknowledged Australian source for
attractively patterned agates that occur in and are weathered from amygdaloidal basalt of
Carboniferous age. Agate Creek agates are renowned both for the beauty and diversity of
their attractive colour patterns. It is a pity that agate from Agate Creek in North
Queensland is little appreciated outside of Australia, for this agate displays nearly
every conceivable colour and pattern that is possible to observe in agate.
About a century ago, early prospectors searching for gold in the Gilberton area to the
south of Georgetown, found an abundance of amygdule-derived nodules of agate that had
accumulated in one of the creeks that flowed into the Robertson River. These agates had
weathered and eroded from basalts of Carboniferous age that were overlain by a thick
sedimentary deposit of Hampstead Sandstone This 235 million year old sandstone has a
surface area of approximately 80 km2 . The creek in which the agate nodules
were discovered soon became known as Agate Creek. The occurrence of agate at Agate Creek
was first reported, as an observation, by W.E. Cameron in his G.S.Q. Report No. 151, dated
At the time of discovery of this large deposit, no significant value seems to have been
attached to its agate, for the worlds supply of rough agate came from either the
ancient mines surrounding Idar Oberstein, in Germany, or from newly discovered deposits in
Brazil. These agates were processed and sold by the traditional lapidaries of Idar
After World War 2, an attempt was made to use heavy machinery to mine the Agate Creek
deposits for commercial purposes. The limited success of these operations was tempered by
that fact that at that time the hobby of lapidary was becoming increasingly popular in
Australia. As a consequence, the Agate Creek deposit became a target by enthusiastic
fossickers, who appreciated the low cost of self-dug agate. In retrospect it is indeed
unfortunate that the oft-unbridled enthusiasm of these early fossickers led to the
development of animosity between miners of the agate and those who soon were to be known
as rockhounds. As a direct consequence, subsequent amendments to mining
regulations effectively prohibited the use of any type of machinery to mine agates at
Agate Creek. Today, both professionals and amateurs are free to fossick this deposit -
only with hand tools - for the total cost of the purchase of a Fossicking License from the
Queensland Department of Minerals & Energy offices in Brisbane, Georgetown, or the
goldfield town of Forsayth. It is an indication of the size of the Agate Creek deposit
that significant quantities of good quality, well coloured agate are still being
recovered, sawn, polished, and exhibited.
The Agate Creek agate deposit lies at the head of three creeks - Blacksoil Creek, Spring
Creek, and Agate Creek. Geological features and fossils found in the area drained by this
three creek system indicate that the agates have an age of less than 300 million years.
The amygdaloidal (gas cavity containing) basalt, that flowed over the countryside to an
estimated depth of 50-100 m, crystallised many millions of years before a large inland sea
covered the area to subsequently form the thick sandstone that now covers the original
basalt flows. It was the subsequent leaching of silica from this sandstone that filled the amygdules within this basalt and set the stage for the formation of the Agate Creek
The three creek system, that drains this lightly timbered savanna country, has a length
of approximately 26 km and generally runs in a north westerly direction to join the
Robertson River about 40 km south-south-west of Forsayth. The Robertson River ultimately
drains into the Gulf of Carpentaria once it joins the Gilbert River.
Today, a graded gravel road and tracks lead the intrepid fossicker to the Agate Creek
agate field. These roads and tracks are quite suitable for conventional vehicles during
the drier May to September winter months in Australia.
A Mining Guide, presently available from the Queensland Department of Minerals &
Energy office in Georgetown, indicates that within the 11 x 3 km boundaries of the present
field there are several well known localities at which agates can be mined from either
their primary basaltic source, or alluvial deposits derived from these rocks. Recently,
the area has been gazetted the Agate Creek Fossicking Area.
Features & Characteristics of Agate Creek Agates
Agate, a chalcedonic variety of the mineral quartz (silicon dioxide or SiO2),
has a cryptocrystalline structure, and is it is formed from oriented bundles of
submicroscopic fibres of quartz. Agate has the following identifying gem gemmological
properties and features:
2.57 to 2.64
Most Agate Creek agates
display a concentric banded structure, however seam agate, tube agate, moss agate, and
dendritic agates are found commonly. Banded onyx and sardonyx can also be found in nodules
of Agate Creek agate. While some Agate Creek agates consist of solid agate, others either
have interiors filled with colourless quartz crystals, or are partly hollow and lined with
crystals of amethyst, aragonite, or even calcite.
In the Agate Creek valley, no two agates are the same; but agates found in the same
primary locality may display certain features that allow the expert to identify the
location from which the agate was removed. Indeed, some agate buffs can
examine an agate and inform you from which hill or creek a particular agate came from!!!
Some Agate-bearing Localities at Agate Creek
Within the approximately 45 km2 area of the Agate Creek Fossicking Area several
well known agate-bearing deposits have been recognised. These localities, and their
characteristic agates include:
Flanagans, located on a hill a short walk to the south-east of the well
appointed Safari Camp that services this fossicking area. This deposit was host to one of
the first commercial mines, yet it still yields good quantities of red, green, and
white-banded agates - many displaying inclusions of haematite and with distinctive
Simpsons, another previously commercially mined area that is located about a
kilometre north- west of the Safari Camp. On the right hand side of the track that leads
to this deposit, nodules containing porcelain-pink and white agates can be found in an
area where past miners have removed large amounts of overburden that contained large
Blue Hills, located directly across the valley to the south of
renowned for its blue agates with pink or red centres. These agates must be recovered from
rather large previous excavations.
The Spring Creek area is accessed to the left off the main track that winds
westwards down Agate Creek from the Safari Camp. For a long time Banyan Springs, located
on one of the small feeder creeks to Spring Creek, has been a major source of fresh water
for the area. This area is renowned for the variety of its agates. These include: straight
banded agates - particularly those of the sardonyx variety; thunder eggs infilled with straight banded agate, agates concentrically banded in reds, greens, and
creams, moss agate and tube agate.
Bald Hills and Black Rock are two features on a range of hills to the
north of Agate Creek that divide the Agate Creek valley from Blacksoil Creek valley
further to the north-west. Black Rock, the most prominent feature, is located about 4 km
NW of the Safari Camp. At both these localities carnelian agates, some containing quartz
crystals, may be recovered. Darker red and blue agates, with "a suspended agate
pattern", also may be found at this locality.
The Saddle, located at the eastern end of the range of hills a little under 2 km
north-west of the Safari Camp, is a long established source of agates. Here yellowish
green agates and red agates are eagerly sought. Some of the agates from this locality tend
to be stained with patches of pale blues, reds and yellows, thus enhancing
their uniqueness and beauty.
About 7 km along the north-west trending track from the Safari Camp, a small track to
the right passes around a small isolated hill known locally as Crystal Hill. Here,
colourful seam agates, tube agate, and nodules of red agate with quartz and aragonitic
cavity infillings have and are still recovered from time to time.
Agate Creek, itself, is a prolific source of flood or eroded agates.
As the road/track access from Forsayth to the Safari Camp crosses Agate Creek at least
eight times, a diligent search of the alluvial gravels at these crossings often will yield
choice agates that have been weathered from their parental basalt and transported by the
waters that flood Agate Creek during the wet season. The best time to locate
agates, in Agate Creek, is during the winter dry season (May to September) when the creek
will be dry.
At about 10 km along the track towards Forsayth, a track to the right leads to the Black
Soil Creek valley, yet another prolific source of agates. This valley hosts many
localities at which colourful agates can be obtained with a little digging. A virtual
"rainbow of agates" occur in the Black Soil valley. At the far (northern) end of
this valley, agate-bearing thunder eggs, that are strikingly patterned in red
and cream, occur in a location that is yet to attract a popular name.
Possible Causes of Colour
It would appear that the various oxides of iron play in important role in colouring many
of the agates from Agate Creek. Consequently reds, and various shades of red, seem to
predominate in Agate Creek agates. Indeed, when the colours caused by iron are combined
with other colours due to the oxides of other transitional elements, a virtual rainbow of
colours is not only possible but is created in Agate Creek agate.
Agate Creek agates come in all sizes and shapes. However, most agates from this deposit
are somewhat ovoid in shape and range from pigeons egg to football size.
While football sized Agate Creek agates are quite rare, the average sized agates from
this deposit seldom exceeds 50-70 mm in length. One observation worth recording is that
the larger the agate, the more irregular its shape is likely to be.
From the lapidary viewpoint, although the agates of Agate Creek appear to be quite dense,
stress fractures that may appear after sawing and polishing can devalue these otherwise
beautiful agates. Agate Creek agates occur in a wide range of colours and colour patterns.
But, when rarely found, somewhat chatoyant and gold flecked varieties of agate are the
real find when you go fossicking at Agate Creek.
North Queenslands Agate Creek Fossicking Area hosts a little described agate
resource of world significance. Although generally small in size, the vibrantly coloured,
attractively patterned agates from many individual deposits that are scattered throughout
this area have an aesthetic appeal that is second-to-none.
Bates, R.L. and Jackson, J.A. (1987) Glossary of geology. pp. 10. 3rd ed., American
Geological Institute: Alexandria, Virginia.
Burchester, K.J. (1965) The Australian gemhunters guide pp. 138-143. Ure-Smith:
Cameron, W.E. (1900) Geological map to accompany a report on the Etheridge and
Gilbert Goldfields. Geological Survey of Queensland Report 151.
Hutchinson, G.H. (1965) A prospectors guide to agates at Agate Creek. Queensland
Government Mining Journal. 66, 517-519.
Stone, D. (1969) How to find Australian gemstones pp. 93-97. Periwinkle Press:
Australian Gem Gallery