HPHT diamonds will continue to pose problems for the industry, a panel agreed at The JCK Show on Wednesday.

“If I was a retailer, I’d be scared to death of these stones, because you probably can’t identify them in your store,” said moderator Gary Roskin, JCK senior editor.

David Hall, who used to produce HPHT greens for his company NovaDiamond, called the technology a “rebirth process” for diamonds, because it replicates the conditions in which diamonds are formed. But he said the company eventually had to leave the market because it didn’t know how to market or cut the diamonds. He also found that a lot of people were treating diamonds and not indicating that they were treated.

“They would come to us and sometimes even the labs wouldn’t detect it,” he said. “The way to make money in this industry is to not tell people. If you plot the number of special-colored diamonds that come up at auctions, it follows the growth of the high-pressure industry. We thought we had made this great discovery, but it turned out this has been going on for some time and we were just the newcomers.”

Branko Deljanin, research director at European Gemological Laboratory, told the crowd that the presses to make these stones are becoming more sophisticated, less expensive, and more common. He added that identification of HPHT color-enhanced diamonds is more demanding than the identification of other types of gem treatments.

A diamond’s receptivity to high pressure and temperature treatments depends on its “type.” Nitrogen- and boron-free type IIas can be made into colorless and pink stones. Type IIbs, which have boron but not nitrogen, can be made blue. Both these types are very rare.

Approximately 98% of all diamonds are Type Ias. Brown Ias can be changed into yellow or “neon” green.

Nearly every panelist warned that jewelers have to be more aware of what they buy. “If a diamond has an interesting color, you better look at it twice,” Hall said.

JCK