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Color distribution in nitrogen-doped CVD after irradiation and annealing
Diamond Identification

Poster abstracts on “Diamond Identification” from GIA’s 2018 International Gemological Symposium.

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Canary yellow diamond
Diamond Identification

Abstracts of speaker presentations from the “Diamond Identification” session of GIA’s 2018 International Gemological Symposium.

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Single-crystal CVD diamond
New Technologies and Techniques

Abstracts of speaker presentations from the “New Technologies and Techniques” session of GIA’s 2018 International Gemological Symposium.

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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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Irradiated 1.06 ct brownish orange HPHT synthetic diamond
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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5.19 ct CVD synthetic diamond
CVD Synthetic Diamond Over 5 Carats Identified by GIA

Results from GIA’s recent testing of a 5.19 ct CVD synthetic diamond, the largest it has examined to date.

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Article
Identifying Lab-Grown Diamonds

Dr. James E. Shigley describes the means of distinguishing colorless and colored synthetic gem-quality diamonds from natural diamonds.

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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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5.03 ct Fancy Deep Blue HPHT Synthetic Diamond
Largest Blue HPHT Synthetic Diamond

Analysis of a 5.03 ct HPHT-grown blue synthetic diamond, the largest ever examined by GIA.

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