GIA Confirms New 34.59 Ct. Diamond is Largest Known CVD Lab-Grown

The GIA (Gemological Institute of America) announced today that its laboratory in Hong Kong recently evaluated the largest chemical vapor deposition (CVD) laboratory-grown diamond seen by GIA.

The 34.59 ct. diamond is more than twice the size of the last largest CVD-grown diamond—which was a 16.41 ct. gem the GIA evaluated in 2022. 

The new emerald-cut diamond measures 24.94 × 13.95 × 9.39mm and was produced by Ethereal Green Diamond in India. It’s been evaluated as VS2, G color. Researchers found “small black graphite inclusions, some along the inside of the body, while others formed clusters of clouds between growth layers,” according to a GIA statement. “Microscopic observation showed a weak ‘oily’ or wavy graining looking through the table, a feature sometimes seen in CVD laboratory-grown diamonds.”

“This more than two-fold increase in size within one year is an impressive technical achievement in CVD diamond growth,” said Tom Moses, GIA executive vice president and chief laboratory and research officer, in the same statement. “With such production improvements, correct identification and disclosure are critical to maintaining consumer trust; this is another example of why GIA devotes significant resources and research to protect consumer confidence.”

GIA’s quarterly journal, Gems & Gemology (G&G), published an online research note on the diamond that includes all observations and spectroscopic features—the note will also appear in the journal’s summer 2023 print edition.

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