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Describing 58-facet Round Brilliant-Cut Diamonds at GIA

Many beautiful older diamonds are cut to different proportions than modern round brilliants, which makes them a challenge to grade according to modern cut conventions. This article describes how the GIA accommodates these historic gems.

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The Wittelsbach Blue

This article describes what is known about the Wittelsbach Blue since it was first reported in 1666, and the gemmological information released to date on this diamond.

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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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Article
De Beers Reduces Rough Prices – Too Little?

De Beers reduces rough prices at May sight, undisclosed treated diamonds submitted to GIA, and Sotheby’s and Christie’s sales break auction records − again.

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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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Characterisation and Grading of Natural-Colour Pink Diamonds

Known for their great beauty and rarity, pink diamonds have long been sought after by jewellers, collectors and consumers.

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Grading the Hope Diamond

One of the most popular exhibits at the Smithsonian Institution, the stunning Fancy Dark greyish blue Hope diamond was formally graded by GIA’s gem laboratory.

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Computer Rendering of the “French Blue” Diamond
The French Blue and the Hope: New Data from the Discovery of a Historical Lead Cast

With the use of modern tools and technology, this article sheds light on the history and provenance of both the French Blue and the Hope diamonds.

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Colour Grading of Coloured Diamonds in the GIA Gem Trade Laboratory

How GIA’s Gem Trade Laboratory grades coloured diamonds, including an expanded colour grading terminology, is explained.

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Abstract Header from the 2009 issue of Gems & Gemology
Abstracts; Autumn 2009

This article, from the Autumn 2009 issue of Gems & Gemology, is a compilation of abstracts of important gemmology-related articles published outside of Gems & Gemology.

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