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Titanium-coated tanzanite
Titanium-Coated Tanzanite

For the first time, GIA's laboratory has examined tanzanite color-coated with titanium.

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Large sunstone rough from the Ponderosa mine in Oregon
Ponderosa Sunstone Update

John Woodmark provides an update on the Ponderosa sunstone mine in Oregon.

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Turquoise with Fingerprint Pattern

A fingerprint pattern, possibly left by human skin oils during the assembly process, is observed in natural turquoise beads.

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Solution-Generated Pink Color Surrounding Growth Tubes and Cracks in Blue to Blue-Green Copper-Bearing Tourmalines
Solution-Generated Pink Color Surrounding Growth Tubes and Cracks in Blue to Blue-Green Copper-Bearing Tourmalines from Mozambique

Several transparent, faceted, blue to blue-green copper-bearing tourmalines containing growth tubes and cracks surrounded by sleeves of pink color were examined for this report.

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Rough blue spinel crystals from Luc Yen
Blue Spinel from the Luc Yen District of Vietnam

Offers geological context and gemological characterization of this increasingly popular vivid blue spinel from northeast Vietnam.

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Vanadium and Chromium-Bearing Pink Pyrope Garnet: Characterization and Quantitative Colorimetric Analysis

This type of pink pyrope garnet, believed to have been mined in Tanzania, shows a distinct color-change phenomenon resulting from its unique chemical composition.

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Santa Terezinha De Goias Emeralds
The Santa Terezinha De Goias Emerald Deposit

Brazil has become a leading producer of emeralds; this article examines one of the most significant deposits.

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Natural-Color Pink, Purple, Red, and Brown Diamonds: Band of Many Colors

Summarizes data collected by GIA on more than 90,000 natural diamonds in this color range and presents their gemological and spectroscopic properties.

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Color-change diaspore
The Color Origin of Gem Diaspore: Correlation to Corundum

Examines the color origin of color-change diaspore, known commercially as Zultanite, and compare the effectiveness of the chromophores it shares in common with corundum.

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Mozambican ruby with signs of heat Treatment
Colored Stones and Pearls

Poster abstracts on “Colored Stones and Pearls” from GIA’s 2018 International Gemological Symposium.

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