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Lab Identifies First CVD Synthetic Diamond Over One Carat

posted May 10, 2010, 7:32 AM by Alex Barcados
This G-color CVD synthetic diamond weighs 1.05 ct. Photo by Jian Xin “Jae” Liao.
Single-crystal CVD synthetic diamonds are occasionally submitted to the GIA Laboratory for identification and grading reports. For the first time, the New York lab has identified a near-colorless CVD-grown diamond larger than a carat that was submitted for grading.
This 1.05 ct pear shape (9.81 x 5.95 x 3.06 mm) was color-graded as equivalent to G. In addition to pinpoint inclusions, it contained some feathers and fractures along the girdle, and its clarity grade was equivalent to I1. No fluorescence was observed when it was exposed to conventional long- and short-wave UV radiation. The infrared absorption spectrum indicated that the sample was type IIa. Images taken with the DiamondView, which employs strong ultra short-wave UV radiation, showed strong orange-red fluorescence with some irregularly shaped regions of blue fluorescence. Photoluminescence spectra collected at liquid-nitrogen temperature with laser excitations from the UV to IR regions revealed features typical of a CVD synthetic diamond, and this identification is consistent with its other properties.
Clearly, CVD synthetic diamonds of better quality and size are being produced as the growth techniques continue to improve.
- Wuyi Wang and Kyaw Soe Moe
GIA Laboratory, New York