Fall 2017 - Volume 53, Issue 3
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Major colors of HPHT synthetic diamonds
Observations on HPHT-Grown Synthetic Diamonds: A Review

Summarizes statistical data and distinctive features of several thousand gem-quality HPHT synthetic diamonds examined by GIA from 2007 through 2016.

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Drilled natural pearls examined in this study.
Saltwater Pearls from the Pre- to Early Columbian Era: A Gemological and Radiocarbon Dating Study

Examines 85 saltwater natural pearls, reportedly harvested from the Caribbean islands off the coast of Venezuela during the early 16th century, to determine their age.

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Dalmatian stone samples
True Colors of “Dalmatian Jasper”

Discusses the mineralogical composition and provenance of this spotted decorative gemstone.

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Cross-like cloud pattern in diamond.
Unusual Cloud in Diamond

A diamond with a previously unseen clarity characteristic is seen in GIA’s Carlsbad lab.

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Quartz silver pendant with hematite inclusions.
Hematite in Quartz: “A Rose by Any Other Name”

A quartz cabochon hosts an unusual rose-shaped hematite inclusion.

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Natural surface growth marks on Brazilian beryl.
Awards for James Shigley and Jonathan Muyal

Two regular G&G contributors receive awards for their work in the field of gemology.

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Colombian independent miners
Colombian Emerald Industry: Winds of Change

A firsthand look at Colombia’s emerald mines and the cutting and trading industry in Bogotá.

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A blue synthetic star sapphire from past production of Wiede’s Carbidwerk
Synthetic Star Sapphires and Rubies Produced by Wiede’s Carbidwerk, Freyung, Germany

Details the process used by Wiede’s Carbidwerk to produce star synthetic corundum from the mid-1950s through the 1970s.

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Letters: Note on CVD Synthetic Overgrowth

A response to the Summer 2017 Lab Note on CVD synthetic overgrowth on a natural diamond.

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Emerald crystals from Colombia, Afghanistan, and Zambia
Photoluminescence Spectra of Emeralds from Colombia, Afghanistan, and Zambia

Compares PL spectroscopy data of 48 emerald samples from three countries to evaluate the usefulness of the technique in geographic origin determination.

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