The Gemological Institute of America (GIA) reported the “largest” CVD synthetic diamond it has examined to date, after the stone was submitted for grading without notification of its lab-grown origin.
The cushion modified brilliant, 5.19-carat diamond with J-equivalent color and VS2-equivalent clarity was submitted at the GIA’s Hong Kong laboratory. The stone contained natural-looking internal inclusions such as needles and clouds and could have been mistakenly identified as natural based on microscopic examination alone, the institute said.
“This case therefore highlights the importance of using advanced spectroscopic instruments as well as conventional gemological techniques to ensure an accurate identification,” the GIA said.
In September, the GIA also examined a 10.08-carat synthetic diamond, the largest high pressure, high temperature (HPHT) assessed by the institute.
BRON: Rapaport 18-10-2016