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  • The 34.59-carat emerald-cut, G-colour, VS2 CVD lab-grown diamond tested by GIA’s Hong Kong laboratory. (Photo courtesy: GIA)

GIA HK Lab Examined 35ct. CVD Diamond

The Gemological Institute of America (GIA) has examined a 34.59-carat CVD (chemical vapor deposition) lab-grown diamond, the largest CVD lab-grown diamond GIA has encountered, recently in its Hong Kong laboratory.


The emerald-cut, G-colour, VS2 lab-grown diamond was produced by Ethereal Green Diamond in India. The stone exhibited qualities consistent with a CVD, type IIa diamond. GIA said, small black graphite inclusions were found. Some stood alone inside the body, while others formed clusters of clouds located between growth layers. Microscopic observation showed a weak oily or wavy graining looking through the table facet, a feature sometimes seen in CVD lab-grown diamonds. It tends to appear more prominent in CVD lab-grown diamonds with high amounts of strain and a strong birefringence pattern when viewed through crossed polarisers.


Previously, the largest CVD lab-grown diamond graded by GIA weighed 16.41 carats in 2022.


Tom Moses, GIA executive vice president and chief laboratory and research officer said: “This more than twofold increase in size within one year is an impressive technical achievement in CVD diamond growth. With such production improvements, correct identification and disclosure are critical to maintaining consumer trust.”



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