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Assortment of Linde synthetic star rubies and sapphires
Dual-Color Double Stars in Ruby, Sapphire, and Quartz: Cause and Historical Account

Examines a form of asterism comprising two six-rayed stars, one white and one that exhibits the stone’s bodycolor. Firsthand accounts and a survey of patent documents reveal that diffusion has been used to create or enhance this optical phenomenon in synthetic and possibly natural corundum since the 1950s.

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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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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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Samples of by-product synthetic zincite
Characteristics of Gem-Quality By-Product Synthetic Zincite

Investigates the properties of synthetic zincite produced by industrial kilns in Poland.

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Richard Nacken in 1907
Synthetic Emeralds Grown by Richard Nacken in the Mid-1920s: Properties, Growth Technique, and Historical Account

Describes the chemical, morphological, and microscopic properties of the first gem-quality synthetic emeralds ever produced, offering a historical perspective on their development.

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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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Three colorless synthetic diamonds weighing 2.02, 2.20, and 2.30 ct
Large Colorless HPHT-Grown Synthetic Gem Diamonds from New Diamond Technology, Russia

Examines a new source of colorless and near-colorless gem-quality HPHT synthetic diamonds using spectroscopic and gemological analysis.

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The 3543 CM-1 Infrared Absorption Band in Natural and Synthetic Amethyst and its Value in Identification

The proper use and limitations of IR spectroscopy for identifying natural versus synthetic amethyst of various types have been investigated, focusing on the region 3800–3000 cm-1.

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0.45 ct Pink CVD Labgrown Diamond
Strongly Colored Pink CVD Lab-Grown Diamonds

Pink CVD lab-grown products can be separated from natural and treated-color natural pink diamonds by a combination of gemological and spectroscopic properties, which are explored in this study.

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Faceted CVD Synthetic Diamonds
CVD Synthetic Diamonds from Gemesis Corp

An examination of the gemological and spectroscopic properties of CVD synthetic diamonds from Gemesis Corp.

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