Explores the potential of laser Raman spectroscopy for material identification in pearls as well as determining the orientation of their biogenic mineral growth.
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While top-quality natural spinels have so far escaped large-scale treatment processes, some heat-treated goods are on the market. This report establishes the identifying criteria of heated spinels.
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A collection of rare jeremejevites, reportedly from Namibia, was recently brought to the GIA laboratory in Bangkok for research purposes. This article reports on initial testing of five samples and photos of the entire collection.
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Examines the geographic origin of feldspar based on chemistry and refutes allegations that Mexican material is being sent to China for treatment and sold as Chinese material. Samples from Mexico, Mongolia and the United States are analysed.
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Describes a pink sapphire with natural beryllium and a yellow sapphire with an indeterminate beryllium source
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Describes several rubies treated with glass and experiments on rubies treated with glass, demonstrating that the stones are bonded together by the glass.
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Examines what happens to secondary fluid inclusions (also known as "fingerprints") at extremely high temperatures, and their usefulness in detecting heat treatment.
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An examination of seven CVD synthetic diamonds with an attractive pink colour.
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A preliminary examination and comparison with rubies and pink sapphires from other deposits in Central Asia.
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A summary of two expeditions to the important ruby and sapphire deposits of Pailin, in late 2008 and early 2009. Includes a look at rough and faceted samples.
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