Professional Jeweler Archive: Code Orange, Yellow, Blue and Red... for Corundum

April 2003

First Run


Code Orange, Yellow, Blue and Red... for Corundum

Topping the political agenda at Tucson this year was the issue of beryllium diffusion in corundum


The controversy over beryllium-diffusion treatment of corundum culminated in a summit of worldwide gemological laboratories during the Tucson gem shows in February. The issue is significant because beryllium can affect up to 90% of all sapphires (including blues) in some way, according to recent research by the Gemological Institute of America.

Non-disclosure of the new treatment has affected sapphire sales negatively, particularly yellow, orange, orange-pink and padparadscha sapphire colors, which were the first beryllium-diffused colors to appear in Thai gem markets last year.

Because recutting these treated gems could affect their color, jewelers must abide by the FTC Guides for the Jewelry Industry, which require disclosure of gem treatments that have special care requirements.

Thai group endorses disclosure

The Chanthaburi Gem & Jewelry Association – whose members are Thai labs, treaters and gem dealers – had, for more than a year, resisted acknowledging beryllium diffusion was being used to treat corundum in Thailand. In late February, however, the association agreed that:

  • Chrysoberyl is intentionally added to the crucible during the new heat treatment to enhance color in corundum. [Note: More than a year ago, Thai treaters discovered by accident that adding beryllium-containing chrysoberyl to corundum, during high temperature heating, causes the color to deepen or change in some sapphires.]
  • All association members are obligated to disclose and differentiate the new treatment when selling. CJA introduced a new code system for corundum to acknowledge the diffusion process. Those found not to be disclosing the treatment will be expelled from CJA.

Lab summit in tucson

Identification and disclosure were central to the discussions. Debate continued as to what to call the treatment. GIA calls it “beryllium diffusion” while the American Gem Trade Association Gemological Testing Center and scientist John Emmett favor “diffusion (bulk/lattice) treatment.” Jewelers of America, the American Gem Society and the Jewelers Vigilance Committee followed AGTA’s lead. Despite the difference in nomenclature, AGTA, JA, AGS and JVC issued a statement urging complete disclosure, noting:

  • The international scientific and gemological communities confirmed the “new” treatment used on certain corundum is a diffusion (bulk/lattice) treatment. The additives used create new and alter existing colors.
  • According to the FTC Guides and industry practices, this treatment must be disclosed at point of purchase by all sellers to all buyers at all levels of the trade.
  • A lack of consistency and/or uniformity in the coloration of some gems means recutting and polishing could have an impact on color (removing the layer of diffused color), creating increased concern for consumers in terms of care requirements.
  • Based on these concerns, trade buyers of corundum should consider establishing written vendor agreements stipulating a requirement for such disclosure and requiring the right to return any corundum treated in this manner if the treatment is not disclosed at the time of sale.
  • U.S. laboratories are engaged in research on this matter, are cooperating with the international gemological community and are committed to continue efforts to identify the treatment, support the trade and protect the consumer.
Ted Themelis, an author and gem-treatment expert based in Thailand, unveiled Beryllium Treated Rubies and Sapphires in Tucson. The book details the beryllium-diffusion process and includes before/after illustrations of different types of sapphires and different types of diffusion. He and other labs contacted by Professional Jeweler cite the need to remain vigilant about future diffusion variations in corundum that might use other light compounds, such as lithium or magnesium. He notes improvements in the color of blue sapphires and rubies have already been confirmed using compounds such as lithium and magnesium experimentally. The book is available for U.S. distribution through AGTA gem dealer Bear Essentials; (800) 753-4367, bearandcara@earthlink.net.

– by Robert Weldon, G.G.

Copyright © 2003 by Bond Communications