The Gemological Institute of America and other industry research institutions have made progress in detecting the Bellataire treatment, but GIA executives stress that the battle is not over.

“Eighteen months ago, we never thought we’d be where we are today,” says GIA president William E. Boyajian. “However, our concerns have not changed. We are more at ease, but we are still on this thing full time. There are new developments all the time.”

The biggest breakthrough was the announcement of a comprehensive detection technique for not only white but also fancy-colored treated stones. Still, this is a complicated technique that’s considered too sophisticated for most jewelers. De Beers is developing a “black box” to identify the stones, but this, too, would be too complex for the industry at large and probably too expensive. Boyajian says it’s better suited to gem labs than jewelers’ counters. “I don’t like the term ‘black box,'” he says. “This is not equipment where you just put it in a box and receive an answer. You have to interpret it and base it on other criteria.”

Jewelers may be better off identifying Type II diamonds and sending them to a lab, says Tom Moses of GIA’s research team. “The easiest way is the transparency to short-wave ultraviolet light,” he explains. “There are simple devices to perform this test.”

Even with the recent advances, only the “vast majority” of Bellataire diamonds are detectable-meaning some still are not. “We have seen a handful of anomalies in there that we don’t understand yet,” says Moses. “They have properties that are slightly different than the others and, we suspect, were probably done by accident.”

The industry can breathe a sigh of relief on one front: Despite widespread rumors, GIA has found no evidence that anyone else-from Russia or elsewhere-has been “whitening” diamonds without disclosing it. “We certainly believe that others are experimenting with it, but mostly with colored diamonds and not as much with decolorization,” Moses says.