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Diamond

Diamonds are among nature’s most precious and beautiful creations.

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Color

Colorless diamonds are scarce—most diamonds have tints of yellow or brown.

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4Cs

Factors used to describe diamonds: Clarity, Color, Cut, Carat Weight

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Rarity

The rarity of one or more of the 4Cs can affect value.

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Octahedron

The crystal shape of a gem diamond is often the octahedron.

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Trigons

Trigons—little triangular depressions—occur only on octahedral faces.

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Growth marks

Diamond’s growth marks help experts separate diamonds from simulants.

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Tools

Research

A wide choker-style necklace of a row of emeralds with rows of diamonds above and below the emeralds.
Article
Spring 2019 Auctions: Premium Prices for Historic Pieces

Gemstones and jewels with historical provenance are bringing the best prices at the spring 2019 auctions.

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People meet and mingle at the entrance to the JCK Show.
Article
Headwinds Slow 2019 Vegas Business, Lab-grown Diamonds Proliferate

Decent demand for finished jewelry, but less for loose gems. Plus: Lab-grown diamonds and responsible, sustainable business practices.

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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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The entrance to the GemGenève show featured a large graphic wall.
Article
Trade Hopes for a Bright 2019 Vegas Show

All eyes are on the upcoming jewelry sales events in the U.S. – the Luxury and JCK shows in Las Vegas – as business slows in other parts of the world.

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Orange-red-purple garnet and green clinopyroxene minerals can be analyzed for specific isotopes to help determine diamond ages.
Diamonds from the Deep: How Old Are Diamonds? Are They Forever?

Age dating diamonds, which have been forming for billions of years, using isotope analyses reveals new information about the deep earth.

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552.7 ct Yellow Diamond from the Diavik Mine
The Largest Diamond Ever Discovered in North America

GIA examines a 552.7 ct diamond from the Diavik mine in Canada.

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Natural diamond with CVD synthetic diamond overgrowth
CVD Layer Grown on Natural Diamond

A composite of synthetically grown and natural diamond was recently identified by the Carlsbad laboratory.

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Rough diamond, yellow in color
Article
Diamond Research Gives Clues to the Formation of the Continents

Mineral inclusions trapped in diamonds reveal the continents’ construction – and helps GIA researchers date diamonds.

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A model holds a large cut-corner square diamond with three fingers.
Article
De Beers Ups Supply, FTC Warns About ‘Eco’ Claims

DeBeers responds to fluctuations, and the FTC issues warnings on laboratory-grown diamonds. Plus: 302.37 ct Graff Lesedi La Rona is revealed.

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A woman sits in front of a computer screen with the DiamondView to her right.
Article
Inside De Beers’ Lightbox Diamonds

GIA researcher analyzes and confirms that De Beers’ Lightbox diamonds are grown using the chemical vapor deposition process.

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