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Article
How Do I Know if the Fancy Melee in My Jewellery is Natural Diamond?

Find out about how GIA is addressing industry concerns over undisclosed laboratory-grown and simulated fancy melee being mixed in with natural fancy melee.

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CVD, HPHT and Natural Diamonds
Article
Is There a Difference Between Natural and Laboratory-Grown Diamonds?

Learn about the differences – and similarities – between natural and laboratory-grown diamonds, and how GIA’s researchers and grading laboratories can tell the difference

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Eight natural-color pistachio pearls
Identification of “Pistachio” Coloured Pearls Treated by Ballerina Pearl Co.

A report on the colour treatment process for these intensely greenish yellow to yellowish-green cultured pearls and the techniques for identifying them.

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Two variscite cabochons from central Tajikistan
Variscite from Central Tajikistan: Preliminary Results

A look at the gemmological properties and chemical composition of this light blue to light green to green gem material, which is suitable for cabochon cutting.

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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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Fluorescence image of Aurora Butterfly of Peace
An Introduction to Photoluminescence Spectroscopy for Diamond and Its Applications in Gemmology

Presents the underlying physics and methodology of this analytical technique, which has become an essential tool in identifying treated and synthetic diamonds.

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Article
Not All That Glitters is Gold — Sometimes it is Mozambican Rubies

Learn about Mozambican rubies, including their mining history, characteristics and market demand.

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A piece of diamond rough with green body color and triangular etchings on the surface.
Article
GIA Researchers Reveal the Secrets of Diamond-in-a-Diamond Mystery

GIA researchers in New York recently had the opportunity to examine one of the most interesting and unique diamond crystals ever found.

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A face-up view of a cushion cut diamond with blue color.
Article
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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A row of various shaped cut and polished pink diamonds.
Article
Why are Pink Diamonds Pink? GIA Researchers Dive Deep into their Crystal Structure

GIA researchers analysed more than 90,000 natural pink diamonds to better understand how these rare and beautiful diamonds formed and got their colour.

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