Vibrantly Colored Gems
Bill Larson of Pala International reports a very strong AGTA Tucson show.
Colombian Emerald Industry: The New Generation
Luis Gabriel Angarita and Edwin Molina share their experiences and perspective on the Colombian emerald industry.
Quarterly Crystal: Cr-Diopside in Diamond
A bright green chromium diopside inclusion is seen in a diamond from South Africa's Kimberley mine.
Type IIa Diamond with Extraordinary Etch Channels
Rare dissolution etch channels are seen in a natural diamond.
Five CVD Synthetic Diamonds Greater Than Three Carats
The GIA lab examines five gem-quality CVD-grown diamonds in sizes that reflect the improving technology of the synthetic gemstone industry.
HPHT-Processed Diamond Fraudulently Represented as Untreated
An HPHT-treated round brilliant diamond with an inscription that presents as a GIA report number is found to be inconsistent with the institute's report, previously issued for an untreated diamond.
Cat's-Eye Demantoid and Brown Andradite with Horsetail Inclusions
The examination of two unusual garnets results in identifications issued for the first time in GIA's colored stone report records.
Fracture-Filled Diamond with "Rainbow" Flash Effect
The material used to fill a large fracture in a diamond yields an unexpected iridescence under two different illuminations.
Natural-Color Green Diamonds: A Beautiful Conundrum
Characterizes diamonds with exceptionally rare natural green color, based on GIA’s extensive database of samples.
Iridescence in Metamorphic “Rainbow” Hematite
Analyzes the substructures that cause the intense iridescence observed in “rainbow” hematite from Minas Gerais, Brazil.
DNA Techniques Applied to the Identification of Pinctada Fucata Pearls from Uwajima, Ehime Prefecture, Japan
Shows how genetic material extracted from small amounts of pearl powder can be a useful indicator of this akoya cultured pearl species.
Zoning In on Liddicoatite Exhibit
An exhibit at the Tucson Gem and Mineral Show dedicated to former GIA president Richard T. Liddicoat (1918–2002).
Preview of Nature Art Science with Paula Crevoshay
Renowned designer Paula Crevoshay discusses artistic influences and her latest creations.
DNA Techniques Applied to the Identification of Pinctada Fucata Pearls from Uwajima, Ehime Prefecture, Japan Supplementary Data
Shows how genetic material extracted from small amounts of pearl powder can be a useful indicator of this akoya cultured pearl species.
Spring 2018 G&G: Color Origin of Green Diamonds, Iridescence in Hematite, and the Outlook from Tucson
A summary of the Spring 2018 issue of Gems & Gemology.
Update on "Low-Temperature" Heat Treatment of Mozambican Ruby: A Focus on Inclusions and FTIR Spectroscopy
Non-Bead-Cultured Pearls from Pinctada margaritifera
A new report from GIA's Bangkok laboratory examines a set of 120 NBC samples stated to be of "Tahitian" origin.
Non-Bead-Cultured Pearls from Pinctada margaritifera
A new report from GIA's Bangkok laboratory examines a set of 120 NBC samples stated to be of "Tahitian" origin.