FGI: No Diffusion, Guaranteed

Fine Gems International, wholesalers of Montana sapphire in Helena, Mont., says its entire inventory of Montana sapphires has been heated—in either a reducing (lower oxygen) or oxidizing (higher oxygen) atmosphere—without the addition of beryllium, titanium, or magnesium. Bob Kane, Fine Gem’s founder and president, writes, “The refusal to use chemicals in heat treatment has been a strict company policy since 1994 when American Gem Corporation first started to use heat treatment. Neither Fine Gems International nor American Gem Corporation, the company from which Fine Gems bought its Montana sapphire inventory, used or uses chemical additives for color enhancement.”

The heat treatment process of FGI’s sapphire inventory was entrusted to Dr. John Emmett, the retired head of the Lawrence Livermore Laboratory in Palo Alto, Calif., who in 1990 launched Crystal Research, a company that developed customized methods to heat corundum. Emmett is now a member of the board of governors for AGTA’s Gem Testing Center and has helped identify many of the new bulk-diffusion-treated sapphires in the market.

According to Emmett and Kane, only heat—with either an oxidizing or reducing atmosphere—is used to induce chemical reactions in stones that already have the impurities (e.g., titanium, sapphire’s bluing agent) needed for color to result. Says Emmett, “The success rate was sufficiently high using heat treatment alone that we decided chemicals were not needed.”