This study characterizes CVD laboratory-grown diamonds from Apollo Diamond Inc. that have strong pink colors produced by high concentrations of NV centers. The samples examined weighed ~0.3–0.7 ct, and their color and clarity grades were comparable to top natural pink diamonds. A combination of optical centers were detected using photoluminescence and absorption spectroscopy. These centers are similar to those seen in previously studied pink-to-red diamonds that have been exposed to HPHT annealing, followed by irradiation and annealing at relatively low temperatures. These pink CVD products can be separated from natural and treated-color natural pink diamonds by a combination of gemological and spectroscopic properties, such as fluorescence color, growth zoning, and absorption features in the infrared and UV-Vis regions.
Submitted by Wuyi Wang
May 5, 2010