Carbonado Diamond: A Review of Properties and Origin

Presents a detailed examination of about 800 samples of carbonado diamond from Brazil and the Central African Republic, including possible models for its genesis.

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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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Characterization of Mg and Fe Contents in Nephrite Using Raman Spectroscopy

Evaluates the usefulness of Raman spectroscopy in distinguishing the color varieties of nephrite based on the relative ratio of Mg to Fe concentration.

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An Update on Tourmaline from Luc Yen, Vietnam

Reviews the characteristics of tourmaline from pegmatites in the Luc Yen district of northern Vietnam.

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Visit Europe’s First Diamond Mine

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Photoluminescence Mapping of Optical Defects in HPHT Synthetic Diamond

Demonstrates the importance of this method in identifying diamond treatments, based on the analysis of PL maps acquired from a brownish orange HPHT synthetic diamond.

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Chart: Inclusions in Natural, Synthetic, and Treated Sapphire

Provides a visual guide to the internal features of natural, synthetic, and treated sapphires.

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Big Sky Country Sapphire: Visiting Montana’s Alluvial Deposits

Documents a visit to the upper Missouri River and Rock Creek sapphire mining areas.

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Book Review: Ruby & Sapphire: A Gemologist’s Guide

Review of Ruby & Sapphire: A Gemologist’s Guide

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A Synthetic Diamond Overgrowth on a Natural Diamond

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Dyed Yellow Beaded Freshwater Cultured Pearls Imitating South Sea Cultured Pearls

A yellow cultured pearl necklace is compared to the work of a producer specializing in freshwater pearls of all colors.

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Sapphires from Northern Ethiopia

A new source of sapphires is found in the Tigray region of Ethiopia.

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Quarterly Crystal: Molybdenite Phantoms in Quartz

Raman analysis identifies unusual inclusions in quartz.

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Partially Hollow Tridacna Blister Pearls with Shells Attached

Blister pearls attached to shells are seen in both the Bangkok and New York laboratories.

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Diamond with Unusual Fluorescence Distribution

A submission to the New York lab yields an unexpected reaction to long-wave UV radiation.

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Christmas Tree–Shaped Internal Feature In Diamond

A laser manufacturing remnant in a Fancy yellow diamond creates a unique specimen.

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Mysterious Iridescence in Aquamarine

A rough aquamarine crystal shows an unexpected phenomenon.

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Colorful Chatoyant Glass

A devitrified glass reminiscent of Victoria Stone is seen during the Tucson gem shows.

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Natural Conch “Rosebud” Pearls

Unique natural conch pearls are studied in the New York lab.

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Book Review: Gem Testing Techniques

Review of Gem Testing Techniques by Alan Hodgkinson.

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