The Gemmological Properties of the Sumitomo Gem-Quality Synthetic Yellow Diamonds
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
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
Examination of the properties of a synthetic moissanite specimen submitted as a black diamond.
Heavily Irradiated CVD Synthetic Diamond
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
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
This article compares some of Chatham Created Gems’ synthetic coloured diamonds to natural diamonds and explains the results.
The “Type” Classification System of Diamonds and Its Importance in Gemmology
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.
Two Fancy Dark Grey CVD Synthetic Diamonds
Examination of two CVD synthetic diamonds with an unusual Fancy Dark grey colour.
CVD Synthetic Diamond with Fancy Vivid Orange Colour
Strong absorptions from N-V centres were the main cause of a CVD synthetic diamond’s pinkish orange bodycolour.
Gems & Gemology’s 7 Most Unusual Encounters from 2019
Check out some of the most interesting and unusual diamonds and coloured stones submitted to GIA’s laboratories in 2019.