Disclosing enhancements is straightforward if you know that the gems have been enhanced. The Winter 2002 issue of Gems & Gemology, published by the Gemological Institute of America (GIA), includes an article titled “Chart of Commercially Available Gem Treatments” by Chris Smith of the Gübelin Laboratory in Lucerne and Shane McClure of the GIA Gem Trade Laboratory in Carlsbad. The article features a wall chart showing a comprehensive list of commercially available treatments for the most commonly used gem materials—and, most importantly, notes whether the enhancement can be detected.

Enhancement disclosure is more important than ever, and some of the enhanced gems listed are so common that you might have forgotten they’re treated. Many are enhanced using treatments that can’t be identified 100% of the time or can’t be detected at all, even by the most sophisticated professional gem laboratories.

To obtain a copy of the gem treatments chart, contact GIA’s G&G department at (800) 421-7250, ext. 7142, or visit www.gia.edu/gandg.