Article Search Results

The Gemmological Properties of the Sumitomo Gem-Quality Synthetic Yellow Diamonds

James E. Shigley, Emmanuel Fritsch, December 1, 1986

Sumitomo Electric Industries is producing gem-quality synthetic yellow diamonds in deep yellow single crystals in sizes up to 2 ct.

A Large Irradiated Green-Yellow Diamond

Wuyi Wang, Paul Johnson, and Emiko Yazawa, GIA, July 1, 2013

GIA's identification of a large diamond as artificially irradiated based on careful spectroscopic analysis and lab database review.

Large synthetic moissanite with silicon carbide polytypes

Kyaw Soe Moe, Paul Johnson, and Ren Lu, January 31, 2014

Examination of the properties of a synthetic moissanite specimen submitted as a black diamond.

Heavily Irradiated CVD Synthetic Diamond

Troy Ardon and Wuyi Wang, October 31, 2014

A look at the first CVD synthetic diamond examined at GIA that has been irradiated to a blue colour.

Identification of HPHT-Treated Yellow to Green Diamonds

Ilene M. Reinitz, Peter R. Buerki, June 1, 2000

Greenish yellow to yellowish green HPHT-treated diamonds exhibited highly saturated body colour, well-defined brown to yellow octahedral graining and visual evidence of heating, among other characteristics.

Lab-Grown Coloured Diamonds from Chatham Created Gems

James E. Shigley, Shane F. McClure, June 1, 2004

This article compares some of Chatham Created Gems’ synthetic coloured diamonds to natural diamonds and explains the results.

Coloured Diamonds in the Aurora Butterfly of Peace Collection

The “Type” Classification System of Diamonds and Its Importance in Gemmology

Christopher M. Breeding and James E. Shigley, June 1, 2009

Knowledge of type allows gemmologists to better evaluate if a diamond might be treated or synthetic, and whether it should be sent to a laboratory for testing.

1.50 ct Fancy Dark grey CVD synthetic diamond

Two Fancy Dark Grey CVD Synthetic Diamonds

Troy Ardon and Sally Eaton-Magaña, October 31, 2014

Examination of two CVD synthetic diamonds with an unusual Fancy Dark grey colour.

CVD Synthetic Diamond with Fancy Vivid Orange Colour

Wuyi Wang and Kyaw Soe Moe, January 30, 2015

Strong absorptions from N-V centres were the main cause of a CVD synthetic diamond’s pinkish orange bodycolour.

A face-up view of a cushion cut diamond with blue color.

Article

Gems & Gemology’s 7 Most Unusual Encounters from 2019

Stuart Overlin, Brooke Goedert and Kellie Giordano, December 13, 2019

Check out some of the most interesting and unusual diamonds and coloured stones submitted to GIA’s laboratories in 2019.

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