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Dalmatian stone samples
True Colours of “Dalmatian Jasper”

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

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Drilled natural pearls examined in this study.
Saltwater Pearls from the Pre- to Early Columbian Era: A Gemmological 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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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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Major colors of HPHT synthetic diamonds
Observations on HPHT-Grown Synthetic Diamonds: A Review

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

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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 until the 1970s.

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Near-colorless and Fancy Vivid purplish pink CVD synthetic diamonds
Observations on CVD-Grown Synthetic Diamonds: A Review

Explores statistical data and defining characteristics of gem-quality CVD synthetic diamonds examined by GIA since 2003.

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Two variscite cabochons from central Tajikistan
Variscite from Central Tajikistan: Preliminary Results

A look at the gemmological properties and chemical composition of this light blue to light green to green gem material, which is suitable for cabochon cutting.

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Fluorescence image of Aurora Butterfly of Peace
An Introduction to Photoluminescence Spectroscopy for Diamond and Its Applications in Gemmology

Presents the underlying physics and methodology of this analytical technique, which has become an essential tool in identifying treated and synthetic diamonds.

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Eight natural-color pistachio pearls
Identification of “Pistachio” Coloured Pearls Treated by Ballerina Pearl Co.

A report on the colour treatment process for these intensely greenish yellow to yellowish-green cultured pearls and the techniques for identifying them.

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Identification of Melee-Size Synthetic Yellow Diamonds in Jewellery

Melee-size yellow synthetic diamonds have recently been seen in the gem market.

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