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- Title
CVD Synthetic Diamonds from Gemesis Corp.
- Authors
Wang, Wuyi; D'Haenens-Johansson, Ulrika F. S.; Johnson, Paul; Moe, Kyaw Soe; Emerson, Erica; Newton, Mark E.; Moses, Thomas M.
- Abstract
Gemological and spectroscopic properties of CVD synthetic diamonds from Gemesis Corp. were examined. Their color (colorless, near-colorless, and faint, ranging from F to L) and clarity (typically VVS) grades were comparable to those of top natural diamonds, and their average weight was nearly 0.5 ct. Absorption spectra in the mid- and near-infrared regions were free from defect-related features, except for very weak absorption attributed to isolated nitrogen, but all samples were classified as type IIa. Varying intensities of [Si-V]- and isolated nitrogen were detected with UV-Vis-NIR absorption spectroscopy. Electron paramagnetic resonance was used to quantify the neutral single substitutional nitrogen content. Photoluminescence spectra were dominated by N-V centers, [Si-V]-, H3, and many unassigned weak emissions. The combination of optical centers strongly suggests that post-growth treatments were applied to improve color and transparency. PL spectroscopy at low temperature and UV fluorescence imaging are critical in separating these synthetic products from their natural counterparts.
- Subjects
CHEMICAL vapor deposition; ARTIFICIAL diamonds; GEMESIS (Company); GEMOLOGY; SPECTRUM analysis; COLORS; ABSORPTION; ELECTRON paramagnetic resonance
- Publication
Gems & Gemology, 2012, Vol 48, Issue 2, p80
- ISSN
0016-626X
- Publication type
Article
- DOI
10.5741/GEMS.48.2.80