This Is the Biggest Faceted Lab-Grown Diamond GIA’s Ever Seen
India’s Ethereal Green Diamond grew the 34.59-carat stone, which GIA said represents a milestone in CVD growth.

Grown by Mumbai, India-based Ethereal Green Diamond LLP and submitted to GIA’s lab in Hong Kong, the diamond weighs 34.59 carats and measures 24.94 × 13.95 × 9.39 mm.
“This 34.59-carat CVD laboratory-grown diamond is the largest faceted laboratory-grown diamond GIA has ever seen, CVD or HPHT,” GIA Vice President of Research and Development Wuyi Wang said.
Two employees at GIA Hong Kong, senior staff gemologist Ka Wing Tam and manager of diamond identification Terry “Ping Yu” Poon, detailed the examination of the stone in a research note GIA published online last week. The note also will appear in the summer 2023 print edition of Gems & Gemology.
The emerald-cut diamond was graded G color and VS2 clarity, with small black graphite inclusions inside the body of the diamond and others forming clusters between the diamond’s growth layers.
Fluorescence imaging conducted using the DiamondView, one of the instruments De Beers Group developed for diamond detection, revealed the growth striations typically seen in CVD diamonds, the research notes states.
In addition, microscopic observation showed a “weak oily or wavy” graining in the table facet, a feature sometimes seen in gem-quality CVD diamonds.
The nearly 35-carat diamond is more than twice the size of the 16.41-carat princess-cut lab-grown diamond created by Shanghai Zhengshi Technology Co. Ltd. and examined at GIA’s Carlsbad lab in early 2022.
At the time, that diamond was said to be largest known CVD-grown diamond in the world, though another Indian company exhibited two larger lab-grown diamonds at the JCK show in June last year.
GreenLab Diamonds LLP brought three large lab-grown diamonds to Las Vegas, a trio that included the 20.24-carat emerald-cut “Shivaya” and a 27.27-carat marquise step-cut called the “Om.” The International Gemological Institute graded the stones.
GIA called the creation of this 34.59-carat diamond a “milestone” in CVD growth while noting, “Mined diamonds with similar size and quality are very rare.”
It did, however, highlight one key difference between the 16-carat diamond it examined last year and the much larger lab-grown diamond that just came into its Hong Kong facility.
The 16-carat, princess-cut lab-grown diamond is G color, VVS2 clarity and was not treated to improve its color—which is unusual for CVD diamonds—while GIA researchers confirmed the 34-carat diamond underwent post-growth HPHT annealing to bump it up to a G.
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