‘Lab-Grown’ diamond turns out to be natural


A client of the Gemological Institute of America (GIA) wrongly submitted a natural diamond as a lab-grown stone, the organization said. 
The GIA’s Carlsbad laboratory recently received the round brilliant, 2.23-carat, D-color diamond, which the customer had sent in for a synthetic-diamond grading report.

When a declared synthetic diamond is submitted to a GIA laboratory, it is not often that the diamond turns out to be natural,” GIA analytics technician Garrett McElhenny and senior research scientist Sally Eaton-Magaña wrote in the Winter 2018 edition of Gems & Gemology, the institute’s quarterly scientific journal.

It was easy to mistake the stone for one created using High Pressure-High Temperature (HPHT). It had no clearly visible “strain” under detailed optical inspection — a pattern of lines that is usually absent in HPHT diamonds. The GIA only spotted the feature in a few scattered areas of the diamond following extensive efforts, it said.

Further tests confirmed it was from the earth, but also revealed additional pitfalls: The stone contained dark, natural inclusions that others might have mistaken for metallic flux, a common feature of HPHT diamonds, the institute explained.

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Source Rapaport