Irradiated Mail/Irradiated Gems
Last November the U.S. Postal Service decided to irradiate letters and packages in an effort to kill anthrax spores that might be present in the mail.
What does this irradiation process have to do with jewelry?
The government warned that irradiation might damage some things, such as photographic film, biological samples, food, medicine, and contact lenses. Such items indeed seem mutable and vulnerable, while gems seem rocklike and hardy. However, jewelers are aware that radiation is often used intentionally in the industry to change the color of some gems.
The Gemological Institute of America (GIA) immediately began investigating the potential impact of the process on gems. Jewelers were concerned because the jewelry industry relies heavily on the U.S. Postal Service for shipping jewelry. Even the Hope Diamond, when it was donated by Harry Winston Inc. to the Smithsonian in 1958, was shipped by ordinary mail.
The GIA contacted one of the companies hired by the postal service, a firm known for designing equipment that uses irradiation to kill microorganisms in food. The company agreed to run tests on gems under the same conditions being used by the post office.
The GIA brought 16 gem materials for testing, selecting materials known by experts to be significantly affected by irradiation. The gems were wrapped the way the GIA Gem Trade Laboratory normally packages gems for shipping. Because stones are often shipped more than once (to one place for grading, to another for mounting, etc.), the GIA had some stones scanned one time, some twice, and some four times. They wanted to see if multiple scans had a cumulative effect.
All the samples except diamonds showed dramatic color alterations. Cultured pearls, kunzite, and sapphire showed some of the most significant changes.
Some stones changed as much after a single scan as after four scans. Other stones changed differently with the amount of exposure. For example, colorless quartz that was scanned once became medium brown; a similar sample scanned twice came out dark brown; and the third sample, scanned four times, turned almost black.
The government used irradiation primarily on mail going to the Washington, D.C. area. Now the anthrax scare seems to have abated, so irradiated mail is not a threat to gems at the moment. But in the future it may be necessary to ship jewelry by other means.
However, the more important lesson from these tests is the evidence of how little radiation is needed to produce dramatic color changes. Irradiation is, in fact, a gem treatment that should be disclosed. It is usually used to change or intensify color, making a stone more attractive to the purchaser. In some cases the colors produced by irradiation are not stable and the gem will eventually return to its original color.
With diamonds, irradiation is an inexpensive way to turn off-color, lower-priced goods into richly colored stones. In nature, richly colored diamonds are extremely rare and therefore very expensive. But diamonds colored by irradiation have a value well below—even hundreds of times below—that of naturally colored diamonds. Irradiated diamonds should not be passed off as naturally colored stones.
FOR AGENTS & UNDERWRITING
Irradiation is a treatment that should be disclosed on the appraisal. Irradiated stones do not have the same value as naturally colored gems of similar appearance. If you are insuring a gem of substantial value, be sure the appraisal states that it has not been treated.
FOR CLAIMS
Color-treated diamonds have a value well below that of naturally colored stones. With a claim on a fancy colored diamond of high value, if the appraisal does not specify that the gem was irradiated or otherwise treated, do not assume that it therefore must be naturally colored. Do a careful check before settling the claim. See the January 2001 IM News for specific tips on settling such claims.
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