Undisclosed Synthetic Diamonds Appearing on Market



After more than 600 synthetic colorless diamonds were submitted to the International Gemological Institute without disclosure, the lab is warning the trade about the possibility of more undisclosed stones on the market.

According to an IGI Trade Alert issued last week, the diamonds were grown by the CVD process and submitted to the lab’s facilities in Antwerp and Mumbai. The dealer submitting the stones had no idea they were man-made, and paid prices equivalent to natural diamonds, IGI says.

“I believe there are other undisclosed colorless synthetic diamonds out there,” IGI Worldwide co-CEO Roland Lorie tells JCK. “But we just don’t know how many. I don’t think the volume is huge. You just wonder how this parcel got out there, and how many else are left.”

Lorie adds: “In the past we have received two stones here, three stones there. But it’s always been in small volumes. When you get so many stones, it’s an entirely different story.”

The IGI alert was followed by an alert issued by De Beers’ Diamond Trading Company, which noted that undisclosed stones had also appeared at the National Gems & Jewellery Technology Administrative Centre (NGTC) lab in China.

The stones in question were mostly 0.30 ct to 0.70 cts., F to J color, VVS to VS clarity, and internal characteristics included feathers, pinpoints, and small dark crystals. Polish, symmetry, and cut were either “excellent” or “very good,” with bruted or faceted girdles. All stones were Type IIa, characteristic of CVD synthetics.

“They were just like regular goods,” says Lorie.  “They looked just amazing. Two or three diamond dealers who saw the goods said they would have bought them.”

The alerts note that while gem labs can distinguish synthetic diamonds with tools such as De Beers’ DiamondView, they cannot be distinguished from naturals with standard gemological tools such as loupes and microscopes. Disclosure of man-made gems is required by the FTC Guides.

“Trading in misrepresented or undisclosed products, whether inadvertently or not, could cause irreparable damage to reputation [and] undermine the integrity of the diamond supply chain, damaging both trade and consumer confidence,” said the DTC alert. “These recent events emphasize the importance of having access to methods for detecting synthetics and only buying from sources that can be trusted. Parcels of stones containing unusually high proportions of type IIs should be treated with particular caution.”

It was not immediately clear who produced the diamonds in question. In March, Gemesis began selling CVD-grown colorless diamonds, with inscriptions, from its website.