China’s National Gemstone Testing Center (NGTC) recently tested a new variety of yellow CVD laboratory-grown diamonds. According to NGTC, they tested stones between 1 – 2 ct, the color of the stones varied from pale yellow to dark brownish yellow, including pure bright yellow. NGTC identified some typical inclusions, including pinpoint dark-color inclusions or dark-color inclusions distributed layer by layer. After production, these lab-grown diamonds are processed in high temperature and high-pressure conditions to remove the brownness hue and enhance their transparency. NGTC conducted systematic tests and research on this new variety of CVD synthetic diamonds and announced its results will be published in academic journals soon. The NGTC research team concluded that at the moment, their laboratories can precisely distinguish natural, laboratory-grown, and treated diamonds.
Image Source: NGTC