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| Gems & Jewelry |
All That Glitters
Jill Newman
02/02/2004
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Consumers might be surprised to find out that even the most prominent jewelry houses, including Tiffany & Co. and Harry Winston, will accept certain standard treatments that improve the color of a gem. However, they steer clear of any process that changes the color of a stone, masks inclusions or flaws, or increases the weight of a gem through the impregnation of a foreign substance. Tiffany’s, for instance, accepts heat treatments of rubies and sapphires to improve color and clarity, and the infusion of a colorless substance to improve clarity without increasing the weight of the stone.
 "Anything done to mask any inclusion is not acceptable, because that deceives the eye," says Melvin Kirtley, group vice president at Tiffany’s. "We provide full disclosure of any treatments with every gemstone."
Tiffany’s is employing some of the world’s most advanced technology in its own gemology labs to detect treatments. There are certain standard treatments, such as the heating of corundum (sapphires and rubies) which is considered permanent, according to Kirtley. These are acceptable, but such treatments as resins impregnated in emeralds are not.
Harry Winston sells emeralds that have been oiled, a practice that can protect the stone from cracking, but Ronald Winston, the company’s chairman, is quick to point out that he will not accept colored oils that camouflage the original shade of the gemstone.
"Stones have been oiled or heated for hundreds of years," Winston says. "It’s become almost impossible to find newly mined stones that have not been thermally treated."
Considering the challenges in obtaining natural gems, Harry Winston often turns to estate collections to uncover untreated gems, and they are always accompanied with a laboratory report from a prominent lab such as Gübelin Gem Lab in Lucerne, a gemological consulting lab that serves both the industry and the public.
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