Melee Parcel Contains Just One Natural Stone

RAPAPORT The Gemological Institute of America found just one natural diamond in a melee parcel containing more than 1,000 undisclosed synthetic stones, according to a recent lab note Spectroscopic tests confirmed 1,092 of the 1,093 diamonds to be synthetics created using the High Pressure-High Temperature technique This case represents the largest percentage of undisclosed synthetic melee the GIA has seen in a parcel, researchers Stephanie Persaud, Wuyi Wang, Paul Johnson and Ivana Petriska Balov wrote in the summer 2018 issue of Gems & Gemology, the institute's journal.

"The increase in the amount of synthetic melee submitted - both disclosed and undisclosed - to GIA's laboratories for identification has exponentially increased since GIA began offering its melee-analysis service in 2016," the team wrote More commonly, the GIA receives bags of melee containing a mixture of natural and lab-grown diamonds, or with just a few synthetics - a practice known in the trade as "Salting," the researchers said One notable characteristic of the latest melee batch was the absence of nickel, a catalyst that manufacturers often use in the HPHT process, the team wrote.

"The majority of the HPHT synthetic melee had no detectable traces of [nickel], demonstrating the importance of advanced testing to identify these melees," the authors added. . Source