Irradiated gemstones: Cancer causing jewelery on Asian markets

Nuclear Monitor Issue: 

(December 4, 1997) In Bangkok highly irradiated gemstones were discovered which are being circulated by the hundreds on Asian markets. Many of them are already showing up in finished products in jewelery shops. Tests show that the radiation in some of the stones is more than 50 times the US safety limit. According to medical reports, wearing the jewelery can cause health problems including cancer, because it can destroy white blood cells.

(482.4784) WISE Amsterdam -The so-called "cat's-eye" stones are bombarded with neutrons in a nuclear reactor to change their colour from yellow to a dark brown. This makes them more valuable. A "normal" stone, for example, costs a few hundred dollars per carat whilst the dark brown ones are worth thousands per carat. Methods to change colour by irradiating the stones are legal. But afterwards they must be stored for about two years to let radioactivity decay to a normal level.

In September the Bangkok Center for Gemstone Testing spread a preliminary warning because of abnormally high levels of radioactivity being found in the stones. They suppose the stones involved to have been distributed illegally by unscrupulous dealers who used irradiation for colour enhancement without storing them afterwards. The Bangkok center is saying that anybody who finds such a radioactive stone should store it in a lead lined container until the next century. But how do you find out if the cat's-eye you want to give your loved one for Christmas (or for some other reason) is radioactive? Never mind the fact that most people aren't privy to communiques from the Bangkok center. And where does one find lead lined containers, anyway?

The source of the gemstones is still unknown. According to officials at Bangkok`s Gemstone Testing Center several signs point to Indonesia. It is believed that low quality cat's-eyes from India have been exported to Indonesia to be irradiated there. Indonesia denies the accusations, claiming there is no way to perform the enhancement operations illegally Thailand, India and Indonesia are now all accusing each other of being the country of origin for the stones. However, irradiating stones to change their colour is not limited to those countries; it is also done in other countries such as the Netherlands (for instance at the research reactor at the University of Delft).


  • Reuters, 11 & 12 November 1997
  • AFP, 14 & 17 November 1997
  • UPI, 12 November 1997
  • Milieudefensie (NL), October 1991

Contact: WISE-Amsterdam