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Sapphire Treatment Update

DALLAS, October 9 -During recent months, we at the AGTA Gemological Testing Center have observed that some blue sapphires reaching the US market show indications that they are being treated by a new technique. Most of the gemstones observed range in size from 2 to 17ct. Since these gemstones appear to be coming from Sri Lanka, the AGTA and Sri Lanka dealers and associations are working willingly and cooperatively together to determine the exact nature of the treatment.

Microscopic observations on one of these gemstones show indications of heating, and immersion in methylene iodide revealed a pale blue to near colorless layer closely following the girdle outline. In other gemstones, a much deeper rim of light blue surrounding a deep blue core is seen. The interface between the core and the rim is undulating and delineated by a white line (see figures 1 and 2).

Figure 1

Figure 2

The characteristics may be easily observed when the gemstones are viewed immersed in methylene iodide and illuminated through a diffused light source. This makes it relatively easy to identify the gemstones when buying or sorting. In addition, similar characteristics have been observed in two rubies.

SIMS analyses carried out on several gemstones have not, thus far, revealed a presence of beryllium. Further analyses are presently being carried out in an effort to fully characterize the process.

We have received a great amount of help from US and foreign dealers in providing information on how these gemstones have been treated. This has made the analysis process move along easily and quickly.

If you have information you think can be of help, please contact the AGTA at (800) 972-1162 or email us at

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For further information, please contact:
Douglas K. Hucker, Executive Director
AGTA, PO Box 420643, Dallas, TX 75342
Tel: 800-972-1162 Fax: 214-742-7334

Copyright © 2003 AGTA