Dubai: Synthetic diamonds once used only for industrial purposes have become a growing problem for diamond traders, with a number of undisclosed man-made stones in the market.

But a panel of experts at Dubai Diamond Conference said that although creating gem-quality stones in laboratories was now commercially feasible, the diamond trade, which deals in natural gemstones, had a three-fold approach to protecting their market: detection of lab-grown gems, clear description, and differentiating real stones from artificial ones through marketing.

Ernest Blom, president of the World Federation of Diamond Bourses, said there was no problem with the sale of man-made diamonds, but “our concern is the undisclosed synthetics that are coming into the market.”

Tom Moses, executive vice-president and chief research and laboratory officer at the Gemological Institute of America, said that although diamond factories had been able to create gem-quality stones since the 1970s, the processes became commercially viable with US chemical vapour deposition (CVD) factories around 2000, and particularly high-pressure, high-temperature (HPHT) factories, principally in China, around five years ago.

But although gem-quality stones have become more common, with between three and four million carats of small synthetic stones weighing less than a carat produced each year — about 3 per cent of natural production — the segment is growing.

“This issue isn’t something that’s going away,” Moses added. “It’s like other technology — it’s going to continue to grow and improve, and we’ll see much more of it.”

But detection systems were also improving, he said, with latest machines able to detect even small artificial stones both in rough and cut form.