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Paula Crevoshay’s “Yogo Columbine” sapphire pendant
The Role of Silicon in the Color of Gem Corundum

Considers the previously unreported but critical impact of silicon on the coloration of gem-quality sapphire.

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Indonesian opal cabochons, 6.94 and 3.79 ct.
Opal from West Java, Indonesia

Description of Indonesian opal reportedly from West Java.

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Small unheated spinel and sapphire exhibited by Madagascar Imports
Unheated and Unusual Colors

Margit Thorndal of Madagascar Imports offers her perspective on the colored stone market.

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A 24.96 ct sphene from Zimbabwe (left) and sillimanites from Sri Lanka and Myanmar (right)
Vibrantly Colored Gems

Bill Larson of Pala International reports a very strong AGTA Tucson show.

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Rough CLIPPIR diamonds
The Very Deep Origin of the World’s Biggest Diamonds

Explores an exceptional family of diamonds, referred to as “CLIPPIR” (Cullinan-like, Large, Inclusion-Poor, Pure, Irregular, and Resorbed), that formed in a superdeep environment.

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Article
The Magic of Colored Diamonds

Colored diamonds are in the spotlight. They’re routinely breaking records at auction houses. Learn more about these gemological marvels of the rarest order.

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Accurate Reporting of Key Trace Elements in Ruby and Sapphire Using Matrix-Matched Standards

Presents a group of corundum standards developed by GIA to improve the accuracy and efficiency of its laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) instruments.

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Drilled natural pearls examined in this study.
Saltwater Pearls from the Pre- to Early Columbian Era: A Gemological and Radiocarbon Dating Study

Examines 85 saltwater natural pearls, reportedly harvested from the Caribbean islands off the coast of Venezuela during the early 16th century, to determine their age.

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Dalmatian stone samples
True Colors of “Dalmatian Jasper”

Discusses the mineralogical composition and provenance of this spotted decorative gemstone.

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A round, bright red gem displayed on a dark gray background.
Article
The Red Hot Gems of Summer

These red, pink and orange hued gems evoke passion and excitement – and are surefire accessories for sultry summer days.

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