The Gemological Institute of America (GIA) announced the results of a preliminary study on the impact on certain gem materials of the irradiation process the U.S. Postal Service (USPS) is using to kill anthrax and other biological agents that might be contained in the U.S. mail. In most cases, the process produced dramatic changes in the color of the gem materials.

The testing was conducted with the cooperation of SureBeam, which makes the irradiation equipment the USPS is using. SureBeam is a subsidiary of Titan Corporation, of San Diego. The equipment is a type of linear accelerator that creates a beam of high-energy electrons typically used to kill the microorganisms that can contaminate food.

Coincidentally, this is the same type of ionizing radiation that is often used intentionally to change the color of some gem materials. As a result, the colors of a number of gem materials, among them pearls, sapphire, quartz, kunzite, and topaz, can be sharply altered by the irradiation method the USPS is using, the research showed. For example, the white cultured pearls turned gray, the pale blue sapphires turned deep orange, and the pink kunzites turned green. On the other hand, the diamonds in the study did not show any perceptible color change.

GIA undertook the research as part of its role of serving the gem and jewelry industry and protecting the public interest, according to the Institute’s President, William E. Boyajian. “GIA strives to remain on top of issues that can affect the gem and jewelry industry and the public. When we became aware of the U.S. Postal Service's proposed ‘sanitization’ of mail using ionizing radiation, we immediately began investigating the potential impact of this process on gems shipped through the USPS.”

Boyajian added, “The industry uses the U.S. mail heavily to ship gems and jewelry nationwide, so the potential impact of irradiation on high volumes of mail is obviously a major concern, and we believed it was important to conduct this research.”

Shane McClure, director of West Coast Identification Services for the GIA Gem Trade Laboratory, who led much of the research study, noted, “Our information is that the Postal Service is currently scanning only a small amount of mail using this process, and this has been limited to letters and other flat mail. Nonetheless, we think the results of our research can help the jewelry industry and the public avoid potentially negative effects on their gem materials by choosing packaging that would be less likely to undergo irradiation.”

McClure added, “The preliminary test results also showed that gold jewelry would not retain any residual radioactivity from the irradiation process. GIA plans to continue its research, and further results will be reported when available.”

A detailed report of the actual GIA research, with before-and-after photos, can be seen at the following GIA Web site: www.gia.edu/gandg/special-issue-112701.cfm