The high-tech process has the power to transform the least valuable colored diamonds into the most valuable. That may explain why, after 12 years, it still makes the market uneasy.

Twelve years ago this summer, the HPHT (high pressure/high temperature) process was introduced to the diamond industry, sparking what GIA then-president William E. Boyajian called “the biggest gemological crisis” in his 23 years at the Institute. At the 1999 GIA Symposium, an uproar erupted over the then-­undetectable treatment and its potential to capsize consumer confidence.

Since then, the diamond industry has coped with far more serious crises, and HPHT has remained mostly a nonissue. And while it’s no longer considered undetectable and has yet to generate any negative publicity for the industry, HPHT is still viewed warily by a good portion of the trade. GIA recently shocked the industry by announcing it has seen bigger—often undisclosed—HPHT stones at its grading lab. Meanwhile, the people behind the process complain they’re the victims of unfair, for lack of a better word, treatment. David Bennett, president of Worthington, Ohio–based HPHT producer Bellataire, says his biggest problem is “fighting negativity from people who really don’t understand what the product is.”

So what exactly is the product? The irreversible, permanent treatment, sometimes called “annealing,” subjects brown type IIa stones, which have minute amounts of nitrogen, to enormous amounts of pressure and heat—as high as 2,600 degrees Celsius—to replicate the forces that produce diamonds in nature. After 15 minutes, a stone’s color grade can jump dramatically. If it contains a bit of nitrogen, it can turn yellow or green, or, with the right irradiation, pink. Currently, only two companies openly perform the process in the United States. (Rumors persist of companies doing it not-so-openly overseas; oft-mentioned countries include China, Russia, Korea, and Israel.)

Courtesy of Suncrest Diamonds

Bellataire, which formed in 1999 as a partnership between Lazare Kaplan International and General Electric (GE’s share is now held by an unnamed private equity company), buys type IIa brown diamonds on the open market, treats them, and sells them to wholesalers and retailers. Bennett calls it a “reputable-size” diamond company: “We are not LKI, but we are a nice, profitable business.”

An entirely different model guides the competitor Suncrest (formerly Sundance), which treats diamonds as a service for the trade. The Provo, Utah–based business was formed in 2000 when a dealer approached parent company U.S. Synthetics and asked if it could “whiten” his type IIa diamond with one of its machines. The company could, and a small (seven-person) business was born. Today, Suncrest treats about 15,000 cts. of stones per year.

One of the reasons HPHT remains a modest business is because it works only on brown type IIa stones, and type IIas are rare, accounting for only about 1 or 2 percent of all the diamonds in the world. “Getting rough is one of our biggest challenges today,” says Bennett. De Beers even bars the browns from its sight boxes—“because the color can potentially be enhanced by HPHT,” according to De Beers spokeswoman Lynette Gould.

© GIA
The starting material for the HPHT process is a brown diamond. But not all browns are created equal. These stones, for example, are “from the Argyle mine, which almost exclusively produces type Ia diamonds,” according to the GIA. In order to be effective, HPHT requires rare type IIa brown diamonds.

But other miners consider brown type IIa diamonds hot commodities. “They charge premiums for them, because there is this little niche that is always looking for them,” says Suncrest division general manager Sonny Pope. “So [our customers] pay top dollar, and pray they will get an H or higher.”

Bennett acknowledges that valuing type IIa diamonds can be tricky, because the brown stones are opaque and difficult to see inside. His company is constantly battling “over-payers,” he says, referring to other rough bidders who overestimate how much the color grade will improve in the treatment process. “With HPHT, if you make a mistake, you get killed. We are constantly doing R and D to learn how not to make a mistake.”

Pricing the stones is only part of the HPHT gamble. Low-clarity stones (VS or lower) sometimes crack in the press, though Pope says that happens to only one in 1,000 stones. But it happens. “Every time we put a diamond in the machine, there is a risk,” he says.

The trade, however, is more concerned about the stones being properly identified and sold for what they are. The FTC Guides say the treatment must be disclosed because it impacts the product’s value; both Suncrest and Bellataire require clients to sign an agreement committing to disclosure.

Even so, this disclosure doesn’t always happen, as recent announcements from the GIA confirm. (Pope says that at least one of the stones in question—a 28 carat—was sent in by Suncrest. “I thought they would know, if it came from us, it is treated,” he says. GIA admits it was at fault.)

But the powerful grading lab suspects far murkier motives in other instances and recently banned a number of clients—GIA wouldn’t specify the exact number, but the understanding is that it was at least five—for repeatedly submitting stones without indicating they had been treated. “Our clients have a responsibility,” says Tom Moses, senior vice president of GIA Laboratory and Research. “Disclosing HPHT is part of our client agreement. Every client who submits to us has to abide by it.” GIA stresses that this happens only when someone is suspected of trying to fool the Institute, stating it “does not terminate clients for isolated instances.”

Courtesy of Bellataire
It may be hard to believe these pear-shaped diamonds and the 12.12 ct. fancy purplish pink cushion-cut center were once brown, but Bellataire—which processed them—says believe it.

Even without disclosure, GIA claims it can detect “virtually all” HPHT gems—which, of course, is not the same as detecting “all” these stones. Moses says he can’t estimate what percentage of HPHT diamonds are undetectable, but notes that, in extremely chemically pure diamonds, “there are very few spectroscopic features to go on. That can create a challenge.” In certain cases, GIA has marked the stone’s color “undetermined.”

Suncrest’s Sonny Pope

However, Pope doesn’t consider identification to be a huge problem for grading labs with the proper equipment. “The colored diamonds are especially easy,” he says. “There are always people who say they have seen diamonds get through [undetected], but as far as I know, that is just a rumor.” Bennett agrees: “I have to believe that GIA has a good handle on identification. They have seen thousands and thousands of stones from us. Unfortunately, greed and the challenges of the market sometimes encourage bad things.”

Still, while GIA can spot the stones, the average jeweler or dealer cannot. Moses explains that his lab has a three-pronged approach to detection: the proper equipment, the right people using that equipment, and an “experimental database” of HPHT stones. Without all that, he says, the treated diamonds can be tough to distinguish from their natural counterparts. “For someone who is experienced and looks at a lot of them, there are some indications,” he says. “But just by face value, it’s not that simple.”

Courtesy of Suncrest Diamonds
The HPHT process can turn a brown diamond into a yellow, green, or pink gem, but the bubblegum shades seen above, in a range of diamonds produced by Suncrest, are rare.

Meanwhile, while the trade frets over disclosure and detection issues, the companies who sell HPHT stones say people sometimes ignore their good points. HPHT allows consumers to “get a bigger, better diamond for a lower price,” Bennett says—but he doesn’t offer specifics about how much lower that price is, noting that it varies from jeweler to jeweler.

One retailer who sells the stones tells ?JCK that HPHT-treated diamonds generally retail for about 15 percent less than the comparable non-treated. But he admits the process often gets “a mixed reaction” from consumers. About seven out of 10 people don’t care, he says, but there are some people “who just can’t get past” the fact that they were enhanced. “That a respected cutter like Lazare Kaplan is involved definitely helps,” he adds. “In the end, they are spectacular stones. But they aren’t for everyone.”