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HPHT Treated Diamonds Can Cost Millions

2003: HPHT Treated Diamonds And Demonstration Of Rob Galloway

Oct. 2003

Until now HPHT diamonds were only available fromLazare Kaplan, which marketed them exclusively for General Electric. The companies laser inscribe on their stones’ girdle that the stones are HPHT treated.

Now, however, Sundance—a major player in the industrial synthetic diamond area—is offering a service that will let anyone have their diamond treated. This is a major change that will pose a significant problem for the industry, even though the company will do everything possible to maintain control and integrity.

Last week, Sundance manager Rob Galloway and director of sales and marketing Jim Littman gave us a private demonstration of their technology. Later that day, they gave a demonstration at the Diamond Dealers Club that was standing-room-only, showing the concern that many have about this new technology.

Littman and Golloway showed us how the HPHT process is not so easy as some would believe. It’s not like some colored stone treatments that can be done at home with microwave. (It’s also permanent, unlike many of those processes, which can sometimes rub off on the wheel.) HPHT-treating requires a special press that Sundance says can cost millions.

Furthermore, you can’t just put any brown diamond in the machine and out comes an “F” color. To make a brown come out white, you need a Type IIa diamond, and only a small percentage (1 – 3 %) of the world’s stones fall into the Type IIa category.

The stones also have to be fairly clean, as imperfect stones tend to break under the treatment — which makes us wonder if, in the future, a high color, high clarity stone will automatically be suspect. If the brown stone is not Type IIa, the technology can still make it a better color than it was, but it cannot turn it white — only yellow-green or some other fancy color.

After the treatment, the stones generally have to be repolished, which takes time, money, effort and the possible danger associated with putting the stone on the wheel. Because of this, the treatment is not worth it for full cuts and other small sized stones, because the recutting makes it too expensive.

The biggest danger here is making sure the stones are disclosed as treated. This requires good detection techniques. The GIA and many of the other labs say that they can identify a majority of the treated stones, and we think the technology will eventually evolve so that all stones will be detected. (Sundance is sharing its information with the labs.)

The company also makes its customers sign an agreement that says they will disclose the stone’s treatment. Not disclosing, of course, is contrary to the rules of the trade and the FTC’s Guides for the Jewelry Industry. Yet, like a check, the signature only means something if the person is reliable. This show the importance, once again, of knowing who you are dealing with.

Of course, even if Sundance’s customers all disclose that their stones are treated, it is not the only company in the field. (And of course, there is no assurance that the people that these people trade with will disclose.) So how do you tell? If a stone is Type IIa, that’s a tip-off. A Swiss company is making a machine that can tell if a stone is Type IIa. Type IIa diamonds also typically have a lot of fluorescence. Sundance also has their own more sophisticated machine to detect Type IIas, which they have not yet put on the market. We know a dealer who buys at auction who already tests every stone to see if it’s a Type II.

Of course, if a machine tells you that a diamond is a IIa, it still has to be sent to the one of the labs for testing to see if it‘s treated — but if it’s not, for whites at least, you know you are not dealing with a treated stone. Also, if a stone is SI or lower, that is a sign that it is not treated.


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