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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 bow brooch with long ribbon tendrils.
Article
Bows in Jewelry: The Finishing Touch in Giving

Bows have been a popular motif and finishing touch in jewelry and fashion from time immemorial, recurring and adapting to reflect the style of the era.

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Diamond from Jericho eclogite and Juina superdeep diamond
Diamonds from the Deep: How Do Diamonds Form in the Deep Earth?

G&G’s newest section explores how diamonds form in the deep earth.

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1.15 ct round brilliant diamond
Chart: Inclusions in Natural, Synthetic, and Treated Diamond

Provides a visual guide to the internal features of natural, synthetic, and treated diamonds.

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Suggested Reading on Diamond Inclusions

Suggested Reading on Diamond Inclusions

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The ring is designed with a wavy strip of black diamonds in the center framed on each side with colorless diamonds set in a ruffled edge The earring are crescent shaped with black diamond on the inside framed by colorless diamonds in a ruffled edge.
Article
GIA Researchers Look Inside Black Diamonds

Black diamonds are striking in jewelry. GIA researchers report on the unique properties used to identify black diamonds and the potential treatments.

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CVD-grown diamond with an internal inscription of the Lightbox logo
Gemological Analysis of Lightbox CVD-Grown “White” Diamonds

The Carlsbad lab provides a gemological analysis of two Lightbox CVD laboratory-grown near-colorless diamonds.

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One irradiated CVD synthetic diamond found in a group of 300 irradiated natural melee diamonds
An Irradiated CVD Synthetic Melee Diamond Found in Irradiated Natural Melee Diamonds

Single irradiated CVD synthetic was identified in a parcel of irradiated natural melee diamonds in the Tokyo lab.

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Natural diamond originally submitted as a synthetic
Natural Diamond Mistaken as HPHT Synthetic

Declared synthetic diamond identified as natural in the Carlsbad lab.

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Natural-Color Pink, Purple, Red, and Brown Diamonds: Band of Many Colors

Summarizes data collected by GIA on more than 90,000 natural diamonds in this color range and presents their gemological and spectroscopic properties.

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Synthetic moissanite coated with a thin colored film
Coated Pink Synthetic Moissanite

A pink synthetic moissanite is coated with a thin colored film, raising questions about the natural origin of its color.

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