HPHT Heats Up

Last November, JCK first reported that gem labs were noticing increasing numbers of undisclosed high-pressure/high-temperature-treated (HPHT) diamonds on the market, both near-colorless and fancy-colored. (See "The Heat—and Pressure—Is On," JCK, November 2001, p. 102.) Now the number is growing, and so are concerns.

"The volumes we are seeing are not huge, but it's definitely a concern," says William E. Boyajian, president of the Gemological Institute of America (GIA). "More people are doing it, and they are probably varying the recipes a bit. It's posing more challenges."

New York's European Gemological Laboratory, which is turning HPHT research and grading into something of a niche, sees about 300 treated stones a month, and 30% of them are undisclosed, says research manager Branko Deljanin. The lab knows of at least 10 companies producing the stones—in Russia, Asia, and even the United States.

There are more stones because HPHT technology is improving. For example, treaters are using different presses in addition to the standard ones. "Some of the presses we saw in Russia are unbelievable," says EGL director Mark Gershburg. "They are not very expensive, and [they're] easy to use."

All this raises numerous fears. An industry already taking a beating over conflict diamonds doesn't need a TV show that raises doubts about whether stones are treated. Some at De Beers feel that treatment-type topics could dampen demand even more than social issues like conflict diamonds.

There also are legal perils. Even most gemologists cannot detect an HPHT stone. So a retailer could buy one from a supplier without realizing it and unknowingly break the law when he sells it to a consumer without disclosure. "A year-and-a-half from now, your customer might find out the diamond is treated, and then you have a real problem," Martin Rapaport noted at the recent American Gem Society Conclave in Vancouver.

The solution—a foolproof detection technique—is not yet available. Labs with the proper equipment can detect the diamonds, but there are anecdotal tales of gem labs missing some HPHT stones. Some treaters claim that as many as 10% to 50% of the diamonds are undetectable, but experts dismiss those figures.

"There's no basis for that at all," says Dr. Paul Spear, senior research scientist for the DTC (De Beers) Gem Defensive Program. "It's relatively easy to discriminate the vast majority of these stones."

D-Flawless HPHTs are the toughest to spot, because they have so few characteristics. "There are no inclusions to look at, no defects, no impurities," says Deljanin. His lab may put an "origin of color undetermined" tag on high-color and -clarity Type IIas, similar to what it does for some fancy colors.

Improving technology. So how likely is it you are selling an HPHT diamond without knowing it? Not very, particularly for near-colorless diamonds. The types of diamonds that can be transformed into high-color whites (Type IIa and Iab) account for less than 2% of world production, and not all of these have the required clarity. "The starting material for these diamonds is very rare," notes James Evans Lombe, DTC Gem Defensive Program executive. "And if the starting material is rare, then the stones will be rare as well." Treaters say the competition for brown Type IIa diamonds is intense: "There are so few of those diamonds, you have to be real lucky to find one that wasn't first noticed by someone else," notes Alex Grizenko of Lucent Diamonds, Lakewood, Colo., which is marketing HPHT stones.

Fancy colored HPHT diamonds are easier to produce, since all that's needed is a brown stone. (However, not all browns can be economically treated.) Experts now warn that all fancy colored diamonds should be sent to labs.

There also is talk of developing a "chain of warranties" for untreated stones, similar to the one being developed for conflict-free diamonds, in which each supplier gives the next an assurance that the diamond is untreated. A De Beers statement advises jewelers to "seek guarantees from their suppliers. … If suppliers are unwilling to provide these guarantees, jewelers should seek alternative sources who will provide them."

But Cecilia Gardner of the Jewelers Vigilance Committee, who is helping to design the nonconflict "chain," notes that those warranties are backed up by government certificates, while reports for treatments would not be.

"The whole reason a system of warranties would work for conflict diamonds is because of the governments' involvement at the border," she says. "I'd be concerned about adding a note about a treatment to a warranty that is so vital, so important. If someone is attempting to deceive, this isn't going to stop them."

A long way. As serious as the situation is, the good news is that the trade has come a long way since the treatment was first announced.

"If you remember back in 1999, a lot of people were caught off guard when General Electric announced they were doing this 'undetectable' process," says Grizenko. "Within the last year the labs' level of sophistication and the number they've seen has grown. I don't think that GIA and EGL are catching every last stone, but I suspect the number is getting less and less, and I bet you within the next two years it will be difficult to pass something off."

But until that time arrives, HPHT stones will remain a concern.

"The Russians have more knowledge about this than the entire industry put together," says Deljanin. "Right now, it's a race between the treaters and the detectors. And they're ahead of us."