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Recently discovered and legendary diamonds in the blue/gray/violet color range
Natural-Colour Blue, Grey and Violet Diamonds: Allure of the Deep

Summarises data collected on more than 15,000 natural blue/grey/violet diamonds examined by GIA during the last decade and examines the mechanisms that produce this colour range.

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Fancy Dark brown to Fancy black Marange diamonds
Black Diamonds from Marange (Zimbabwe): A Result of Natural Irradiation and Graphite Inclusions

Characterises a suite of 40 natural brown to black diamonds from this deposit so that they can be distinguished from suspected treated black diamonds.

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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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These three round brilliant diamonds, weighing 0.76, 0.82, and 0.74 ct (left to right), received Very Good cut grades. Each cut grade covers a range of proportions and can therefore have different appearances. Photo by Kevin Schumacher/GIA
Article
Cut: The 4th C

GIA began issuing reports that included a cut grade for round brilliant diamonds in 2006 in an effort to establish standards for cut in the same manner as it has for colour and clarity. This grading system is based on research conducted over the previous decade which was chronicled in several articles published in Gems & Gemology.

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Rough diamonds
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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Article
Famous Diamonds Examined by GIA

An aura of mystery has always surrounded these natural wonders, so it was quite an honour when GIA researchers examined these famous diamonds.

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Today’s round brilliant cut diamonds showcase the gem’s sparkling optics. They’re the most recent expression of a cutting style that has been around for centuries. Photo by Eric Welch, © GIA, courtesy of Signed Pieces, New York
Article
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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RN Linares CVD
Article
CVD-Grown Synthetic Diamonds, Part 2: Properties

This article provides a brief overview of the properties of CVD-grown synthetic diamonds.

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Faceted CVD Synthetic Diamonds
CVD Synthetic Diamonds from Gemesis Corp

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

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GIA’s Symmetry Grading Boundaries for Round Brilliant Cut Diamonds

A presentation of parameters used to support GIA's symmetry grading system.

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