17-08-2018
In a parcel of over 1,000 melees submitted to the Gemological Institute of America (GIA) contained only one natural diamond, with the remaining samples being undisclosed HPHT synthetics, said GIA in its periodical Gems & Gemology, summer 2018 edition.
This has been the largest percentage of undisclosed synthetic melee that GIA has seen, according to the laboratory.
The parcel of 1,102 melee diamonds was sent to GIA’s New York lab for analysis service. Besides the nine stones which did not meet the service’s criteria, the rest of the 1,093 melees were referred for further testing after preliminary screening.
A detailed spectroscopic analysis confirmed that 1,092 of the 1,093 were HPHT synthetics with typical boron-bearing feature. However, no detectable peaks of nickel, normally a catalyst used to grow HPHT synthetics, was shown under the examination using photoluminescence spectroscopy. The absence of detectable traces of nickel in the samples demonstrated the importance of advanced testing to identify these melees, said GIA.
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