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Garnets from Madagascar with a Color Change of Blue-Green to Purple

Gemological, chemical, spectroscopic, and microscopic properties of blue-green color-change garnets from a new deposit near Bekily, Madagascar, are given.

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Celebrating 75 Years of Gems & Gemology

Gems & Gemology, the professional quarterly of GIA, debuted in 1934

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Winter 1995 G&G Book Reviews

“Photo Masters for Diamond Grading”; “A Sparkling Age, 17th Century Diamond Jewellery”

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Infrared Spectroscopy in Gem Identification

The authors describe the new Nicolet 60SX Fourier transform infrared spectrometer recently acquired by CIA'S Research Department.

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An Examination of Four Important Gems

Several famous and historical gemstones in the Smithsonian's collection are examined and reported on.

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Pitfalls in Color Grading Diamonds by Machine

Two major sources of error make spectroscopically determined color grades unreliable.

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Natural Diamond
A Chart for the Separation of Natural and Synthetic Diamonds

Exploration of a chart designed to give jewelers and gemologists a practical guide to identifying synthetic diamonds as they enter the jewelry trade.

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Color Grading of Colored Diamonds in the GIA Gem Trade Laboratory

How GIA’s Gem Trade Laboratory grades colored diamonds, including an expanded color grading terminology, is explained.

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Grading the Hope Diamond

One of the most popular exhibits at the Smithsonian Institution, the stunning Fancy Dark grayish blue Hope diamond was formally graded by GIA’s gem laboratory.

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Characterization and Grading of Natural-Color Yellow Diamonds

A large number of natural-color yellow diamonds are analyzed using grading and appearance aspects among other characteristics to clarify the differences between them and the light yellow diamonds associated with GIA's D-to-Z color grading scale.

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