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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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A heart-shaped piece of pink drusy hangs from a gold chain.
Article
Dreamy Drusy: Minute Crystals Shimmer in Dramatic Designs

Drusy jewellery has surged in popularity in recent years. Celebrities wear it on the red carpet and designers clamour for it at gem shows.

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Suite containing over 36 carats of Yogo sapphire
Gemmological Characterisation of Sapphires from Yogo Gulch, Montana

A look at the mining and distinguishing characteristics of this naturally vibrant blue sapphire.

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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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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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Rough CLIPPIR diamonds
The Very Deep Origin of the World’s Biggest Diamonds

Explores an exceptional family of diamonds, referred to as “CLIPPIR” (Cullinan-like, Large, Inclusion-Poor, Pure, Irregular and Resorbed), that formed in a super-deep environment.

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Colombian independent miners
Colombian Emerald Industry: Winds of Change

A first-hand look at Colombia’s emerald mines and the cutting and trading industry in Bogotá.

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Underground opal mining in Koroit
Splendour in the Outback: A Visit to Australia’s Opal Fields

Documents a trip to the renowned opal fields of Lightning Ridge, Koroit, Yowah and Quilpie.

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Article
Pyrope Garnet and Montana Sapphires Highlight Winter 2015 G&G

G&G Brief presents an overview of the content of the Winter 2015 issue of Gems & Gemology.

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Handful of opal
Article
Lightning Ridge: The World Capital of Fine Black Opal

Lightning Ridge is the world capital of fine black opals, the most desired of all opals. In June 2015 a group of GIA field gemmologists visited this legendary town in New South Wales, Australia. Come with us to explore this important source of fine opals.

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