Very Large Artificially Irradiated Yellow Diamond
Examination of a 59.88 ct irradiated yellow diamond, one of the largest irradiated diamonds identified by GIA.
Evidence of Focused Beam Irradiation in Treated Pink Diamond
DiamondView imaging and photoluminescence spectroscopy offered evidence of focused beam irradiation in a pink diamond.
Treated Pink Type IIa Diamond Coloured by Red Luminescence
A type IIa colour-treated diamond was graded as Fancy brown-pink under daylight conditions and Fancy purplish grey under incandescent lighting, a colour change that resulted from HPHT annealing and irradiation.
Treated Pink Diamond with HPHT Synthetic Growth Structure
A Fancy pink type IIa diamond showing cuboctahedral growth and greenish blue phosphorescence is shown to be a natural, treated coloured diamond.
Yellow HPHT-Processed Rough Diamond
HPHT annealing of a nearly eye-clean yellow natural rough diamond is revealed through spectroscopic analysis.
Spring 2015 G&G Examines Blue Spinel, Chinese Jewellery Design and the Latest in Synthetics
G&G Brief presents an overview of the content of the Spring 2015 issue of Gems & Gemology.
Heavily Irradiated CVD Synthetic Diamond
A look at the first CVD synthetic diamond examined at GIA that has been irradiated to a blue colour.
Diamond, Artificially Irradiated and Coated Brown
Examination of a diamond with a rare and highly sought-after Fancy reddish brown colour revealed that it had been irradiated and coated.
Green Diamond Treated with Radioactive Salt
The stone owes all of its green colour to these shallow radiation stains.
Large HPHT-Treated Fancy Pink Diamond
The New York lab encountered another large HPHT-treated diamond that showed stronger pink colouration.