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A face-up view of a cushion cut diamond with blue color.
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Gems & Gemology’s 7 Most Unusual Encounters from 2019

Check out some of the most interesting and unusual diamonds and coloured stones submitted to GIA’s laboratories in 2019.

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Coloured Diamonds in the Aurora Butterfly of Peace Collection
The “Type” Classification System of Diamonds and Its Importance in Gemmology

Knowledge of type allows gemmologists to better evaluate if a diamond might be treated or synthetic, and whether it should be sent to a laboratory for testing.

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Treated-Colour Pink-To-Red Diamonds from Lucent Diamonds Inc.

Using a multi-step process, Lucent Diamonds has developed a new treatment process for certain natural diamonds that creates colours from pink-purple to red to orangey brown.

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Confusing, Triangular Inclusions in an Art Deco-Style Pin
Spring 1991 G&G Lab Notes

This section, from the Spring 1991 issue of Gems & Gemmology, is a compilation of interesting finds from GIA’s laboratories.

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0.76 ct HPHT-treated Diamond
“Fluorescence Cage”: Visual Identification of HPHT-Treated Type I Diamonds

HPHT-treated type I diamonds of various colours may exhibit unusually intense fluorescence at the facet edges and junctions.

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Hydrogen-rich Diamonds
Grey-To-Blue-To-Violet Hydrogen-Rich Diamonds from the Argyle Mine, Australia

The Argyle diamond mine is the only known source of type IaB hydrogen- and nitrogen-rich diamonds coloured grey to blue to violet.

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