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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

CVD laboratory-grown diamond reaches a new record size at 16.41 ct.
New Record Size for CVD Laboratory-Grown Diamond

The New York laboratory reports on a new record size for CVD laboratory-grown diamond.

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A coated diamond from Orapa, Botswana.
The Discovery of Davemaoite, the CaSiO3 Perovskite, in a Diamond from Earth’s Lower Mantle

Davemaoite identified in a diamond from Orapa, Botswana.

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Blue fluorescence and moderate blue-green phosphorescence seen with the DiamondView.
Natural Near-Colorless Type IIb Diamond

Rare boron-bearing natural diamond identified.

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Brownish orange hematite crystals concentrate along a fracture in diamond.
Hematite Crystals in Diamond

Tiny hematite crystal inclusions identified along two fractures in natural diamond.

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Large type IIa diamonds ranging from 14 to 91 ct.
Deep-Focus Earthquakes: The Heartbeat of a Diamond Factory?

The first installment of this column explores the potential role of modern-day deep-focus earthquakes on diamond growth.

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The type IIb 15.10 ct De Beers Cullinan Blue diamond, graded by GIA.
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The Type IIb De Beers Cullinan Blue Diamond

GIA’s New York laboratory reports on a 15.10 ct (17.47 × 11.53 × 7.94 mm) Fancy Vivid blue cut-cornered rectangular step cut named the De Beers Cullinan Blue diamond.

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16.41 ct CVD laboratory-grown diamond achieves new record size.
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New Record Size for CVD Laboratory-Grown Diamond

GIA’s New York laboratory reports a new record size for CVD laboratory-grown diamond.

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The Portuguese diamond
Measurement and Characterization of the Effects of Blue Fluorescence on Diamond Appearance

Using customized, image-based measurement systems to quantify the effect of fluorescence on the color, brightness, and transparency of gem diamonds viewed in both face-up and table-down orientations.

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Diamonds from the Deep
What Have Diamond Ages Taught Us?

Diamond ages offer insight into continent evolution spanning billions of years.

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A fleur-de-lis motif tiara set with cushion-cut, pear-shaped, rose-cut, and round diamonds.
A History of European Royal Jewel Sales, Including Sotheby’s 2018 Auction of Marie Antoinette’s Jewels

Chronicles important auctions of jewels from European royal collections over the years, with a focus on a recent high-profile sale of items that once belonged to Marie Antoinette.

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