The Society of Mineral
Museum Professionals
SPECIAL ALERT !!!
SPECIAL TRADE ALERT - Update (2 September 1997) HIGHLY RADIOACTIVE CHRYSOBERYL CAT'S-EYE
As reported last Friday, several hundred carats of chrysoberyl cat's-eye cabochon material with an unusual brown color is currently circulating within the Bangkok gemstone market. This weekend much of this potentially dangerous material has subsequently changed hands in the gemstone marketplace in Chanthaburi (Thailand) and is presently working its way into the world gemstone market. The material originates in Orissa (India) and is believed to have been bombarded with neutrons in a nuclear reactor in Asia and released illegally.
The Centre for Gemstone Testing examined one such stone and found it to be highly radioactive. It was erroneously reported to have an activity level of 25,000 nanoCuries/gram (nCi/g) but should have been reported as 52 nCi/g. This is significantly higher than the legal release levels set by the relevant authorities in the USA (1.0 nCi/g) the UK (2.7 nCi/g) and Asia (2.0 nCi/g). Using a Geiger-Mueller tube, this single 3.5 carat stone was found to have a contact radiation level of about eleven ( 11) milliroentgen per hour (11 mR/hr). Subsequent tests have shown it to have a moderately long half-life of approximately one-hundred three (103) days, indicating that this particular stone will reach the legal release level in Asia in another sixteen (16) months (around January 1999). Before that time it must be kept in a properly shielded radioactive materials storage container to ensure personnel safety.
The industry is advised to have all chrysoberyl cat's-eyes of an unusual dark
brown color checked for excessive radioactivity immediately. Traders in Thailand may
submit their stones to the Centre for Gemstone Testing located in the Jewelry Trade
Center. If any stones are found to be above the legal limits, they will be sealed in a
safe container.
Note: Effective 24 August 1997 - The newly formed Centre for Gemstone Testing acquired all of the assets and personnel of AIGS Laboratory in Bangkok (Thailand). Mr. Kenneth Scarratt is the new owner and President.