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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

Kimberlites: Earth’s Diamond Delivery System

Examines the basic characteristics of kimberlites and their relationship with diamonds.

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Scene of a retail street.
Article
Chow Tai Fook Expands Blockchain Initiative with GIA

Chow Tai Fook and GIA offer secure digital blockchain reports that document the diamond journey and grading information in one place.

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Six different shaped red and pink diamonds lined up in a row.
Article
Bank Suspends Credit for ‘Unprofitable’ Rough Diamonds

De Beers and Alrosa slashed rough diamond sales after ABN AMRO’s says it will no longer finance rough purchases for goods that can’t be cut profitably.

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Emerald and diamond brooch.
Article
Jewels of Hollywood: Accessories and Jewelry that Made the Stars Shine

“Jewels of Hollywood,” on loan from the Kazanjian Foundation, showcases some of the jewelry and accessories associated with Hollywood royalty.

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A ruby and diamond choker. The center section is made of six strands of red pearls, framed by rubies and diamonds.
Article
Mughal Jewels Auction: Al-Thani Collection Raises $109 Million

Collectors from around the world descended on Christies’ Maharajas & Mughal Magnificence auction of the jewels from the Al-Thani Collection on June 19.

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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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