Rare Faceted Wurtzite
A stone submitted for identification is revealed to be the first wurtzite examined by the GIA lab.
Fluorite Sphere with Phosphorescent Coating
A sphere with unusual phosphorescence is seen in the Carlsbad laboratory.
A Repaired Diamond
A marquise-cut diamond is found to have been broken and reassembled with an unknown adhesive.
Strong Colour Zoning in Diamond Reflects Complex Growth Environment
A report on a 2.08 ct emerald-cut diamond graded as fancy dark orangey brown.
Rare Faceted Neptunite
Raman spectroscopy reveals orangey red neptunite - the first examined by GIA - in the identification of a 11.78 ct faceted “black” octagonal modified step-cut stone.
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.
Separation of Black Diamond from NPD Synthetic Diamond
DiamondView is used to differentiate a Fancy black natural diamond from its NPD synthetic counterparts.
CVD-Grown Synthetic Diamond with Aggregated Nitrogen Impurities
Recently, an unusual 0.94 ct Fancy yellow-brown emerald was submitted to GIA for a synthetic diamond grading report. It contained a cloud of black needle-like inclusions occurring along a plane and showed weak green transmission with fibre-optic illumination.
Unusual Curved Colour Zoning In Emerald
A report on a 1.17 ct emerald obtained in Kabul, Afghanistan for GIA's permanent reference collection