Gem Lab AG&J finds synthetic diamonds in parcel of natural diamonds for grading

Analytical Gemology and Jewelry (AG&J), a New York-based gemological lab, said that tests on a large parcel of purportedly natural diamond melee uncovered that more than five percent were synthetic diamonds.

The client told the lab that the goods were bought from a well-known company with whom he had been conducting business for many years. The customer did not know that synthetic stones were in the parcel.

AG&J said the package of diamonds had 4,566 round diamonds with a total weight of 56 carats, with sizes from 0.7mm to 2.5mm. The color of the stones varied from fancy intense to vivid yellow with some brownish modifiers, while the clarity range was from VS to SI. The stones were submitted to the lab at the end of December.

The lab used its own melee testing system, which analyzes individual diamonds, and identified 243-HPHT (High Pressure High temperature) synthetic diamonds.

AG&J Chief Executive Officer Dusan Simic said the results showed that all the synthetics came from a single source, and were created for the purpose of committing fraud.

“It was surprising that only four of the 243 synthetic diamonds showed weak magnetic properties, which are the results of metallic inclusions,” says Simic. “In my opinion, this indicates that the synthetic stones were not mixed into the batch accidentally. Non-magnetic diamonds were chosen on purpose because checking for magnetism is one of the quick, low-tech ways to screen melee for synthetics.”

He sad the findings confirm the need to check melee diamonds for synthetics, treatments and imitations. “It is crucial to check every single stone within a batch," she says. "Random screening is not enough. If the end consumer is purchasing jewelry with synthetic diamonds, believing they are natural, then the trade has not done its due diligence in ensuring the proper identity of diamonds traded and sold. Both our ethical obligation and reputation is in question if diamond melee is not screened.”