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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

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

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

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Grading the Hope Diamond

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

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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 honor when GIA researchers examined these famous diamonds.

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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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Rough and faceted natural-color green diamonds.
Natural-Color Green Diamonds: A Beautiful Conundrum

Characterizes diamonds with exceptionally rare natural green color, based on GIA’s extensive database of samples.

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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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Green nephrite man’s ring on a beaded chain
Article
The Nephrite Jade Road: Evolution of the Green Nephrite Market

Along with the skyrocketing price of white nephrite, there is also a developing market for green nephrite in China. However, limited local supply has forced the Chinese to seek outside resources, opening the door to imports of green nephrite mined in British Columbia, Canada, and Siberia, Russia. This has created the well-developed and well-maintained nephrite jade road that connects the three countries, and which is described in this article.

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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 gemological information released to date on this diamond.

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Developments in Gemstone Analysis Techniques and Instrumentation During the 2000s

The first decade of the 2000s continued the trend of using more powerful analytical instruments to solve gem identification problems.

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