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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

Figure 1. With a weight of 0.71 ct and measuring 5.88 mm in longest dimension, this glassy colorless diamond octahedron contains an eye-visible diamond inclusion. Photo by Diego Sanchez.
Quarterly Crystal: Diamond in Diamond

Examination of a South African diamond reveals an eye-visible diamond inclusion.

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Figure 1. This 15.73 ct G-color CVD-grown diamond showed indications of HPHT treatment. Photo by Jian Xin (Jae) Liao.
Large CVD-Grown Diamond Resubmitted after HPHT Treatment

A record holder for largest CVD-grown diamond is examined for a second time in the Carlsbad laboratory after HPHT treatment.

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Figure 1. The pavilion of this 1.67 ct pear-shaped CVD-grown diamond displayed an interesting feature with numerous cloud features resembling lines of text. Photomicrograph by Raju Jain; field of view ~2 mm.
CVD with “Ancient Text” Clouds

A CVD-grown diamond exhibits an interesting clarity characteristic.

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A collection of trigons on the pavilion surface of a round brilliant-cut diamond. Photomicrograph by Isabelle Corvin; field of view approximately 2.0 mm.
Trigon Party on a Diamond

A cluster of trigons is observed on the surface of a 1.01 ct natural diamond.

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Figure 1. The emerald in this ring displays dual-color light green and white double chatoyancy. The stone measures 8.39 × 5.71 × 4.22 mm. Photo by Momo Matsumura.
Dual-Color Double Chatoyancy in Emerald

An emerald displaying dual-color light green and white double chatoyancy is examined in the Tokyo laboratory.

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This patchy cloud with an uneven distribution of pinpoints observed in a natural diamond appears to depict a celestial star. The image was captured in monochrome. Photomicrograph by Tejas Jhaveri; field of view 2.9 mm.
Stellate Cloud in Diamond

Patchy cloud in a diamond resembles a celestial star.

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Figure 4. Face-up image of a 0.08 ct Fancy Light blue type IIb diamond (2.76 × 2.42 mm) with dislocation networks.
The Lengthy Vertical Journey of Superdeep Diamonds

Explores the journey of superdeep diamonds to the earth’s surface.

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Laura Mae, Amanda Jean, and Ilan Portugali are some of GIA’s featured graduates on the Alumni Collective website.
GIA Alumni Collective

The Alumni Collective celebrates GIA alums from all over the world.

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Diamond: Genesis, Mineralogy and Geochemistry, Volume 88 in the Reviews in Mineralogy and Geochemistry series, received this year’s Mary B. Ansari Best Geoscience Research Resource Award.
G&G Contributors Awarded for Best Geoscience Research

Several G&G contributors are recognized for their work on the latest volume in the Reviews in Mineralogy & Geochemistry series.

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Figure 1. Artisanal mining in Liberia. Courtesy of Diamonds for Peace.
Artisanal Diamond Mining: Addressing the Knowledge Gap

Diamonds for Peace conducts basic training on rough diamond grading for artisanal miners in Liberia.

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