International Gemological Institute Hong Kong Branch announced on Monday, November 23, 2020, that their laboratory had graded the largest synthetic Chemical Vapour Deposition (CVD) diamond, which is also the largest synthetic colorless diamond produced by any process, submitted to them by a Chinese Manufacturer, Shanghai Zhengshi Technology. The 12.75-carat, Type IIa, F-color, VVS2-clarity, round brilliant-cut diamond, was cut from a 46.20-carat rough CVD stone, grown by Shanghai Zhengshi Technology.
Gemologists of the IGI, who described the diamond in glowing terms, said, the diamond which can be assigned triple-excellent marks for cut-quality and finish, was of exceptional chemical purity and transparency, with no evidence of any post-growth treatments.
Managing Director of IGI Hong Kong, Bob Van Es, commenting on this lab-grown diamond said, “ A laboratory grown diamond of this carat weight, with such a high clarity and color grade is a remarkable achievement in the area of CVD cultivated diamond technology.”
The Chinese Company, Shanghai Zhengshi Technology, claimed that the diamond was the largest CVD lab-grown diamond ever produced. IGI announced on September 26, 2020, that it had graded the largest lab-grown diamond ever created, by the HPHT process, a 115.65-carat black diamond produced by UK-based Meylor Global, that had set the Guinness World Record for the largest lab-grown diamond in history.