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Dyed Purple Hydrophane Opal

Opals with an unusual purple bodycolor and strong play-of-color have recently appeared in the market.

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Fancy-color diamonds from Lomonosov, Russia.
Geology and Development of the Lomonosov Deposit, Northwestern Russia

Reviews diamond discoveries at the Lomonosov deposit, as well as the geology of the Arkhangelsk kimberlite province.

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The 135.74 ct Grand Sapphire
The Grand Sapphire of Louis XIV and The Ruspoli Sapphire: Historical and Gemological Discoveries

Archival research and gemological characterization reveal the true story of this 135.74 ct blue sapphire from the French crown jewels.

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Beryllium Diffusion of Ruby and Sapphire

The heat treatment of corundum involving lattice diffusion of beryllium (Be) at temperatures over 1800°C has become a major issue in the gem trade.

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Play-of-Color Opal from Wegel Tena, Wollo Province, Ethiopia
Play-of-Color Opal from Wegel Tena, Wollo Province, Ethiopia

A new opal deposit was discovered in 2008 near the village of Wegel Tena, in volcanic rocks of Ethiopia’s Wollo Province.

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Fluorescence Spectra of Colored Diamonds Using a Rapid, Mobile Spectrometer

Numerous natural-color colored diamonds from the Aurora Butterfly of Peace and other collections were studied using a new type of fluorescence spectrometer.

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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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G. Robert Crowningshield: A Legendary Gemologist

G. Robert (Bob) Crowningshield has made many significant contributions to the study of gems and the science of gemology.

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Demantoid and Topazolite from Antetezambato, Northern Madagascar: Review and New Data

An important deposit of andradite, containing demantoid and topazolite varieties, has been mined near the village of Antetezambato in northern Madagascar since early 2009.

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Peridot from Sardinia, Italy
Characterization of Peridot from Sardinia, Italy

Gem-quality peridot is occasionally found as mantle xenoliths within basalts near Pozzomaggiore.

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