叉叉变速齿轮
Phenomenon Resembling Play-of-Color in Sapphire
Subtle tilting of the unheated sapphire revealed a noteworthy phenomenon resembling play-of-color, which is most commonly seen in precious opal.
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GIA Knowledge Sessions
Engage in webinars on the most diverse and pressing issues in gemology today, including gemstone origin, laboratory-grown stones and new discoveries in field gemology.
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Formation of the “Matryoshka” Diamond from Siberia
A freely moving diamond crystal completely enclosed in a diamond from Siberia gets its name from the famous Russian nesting dolls.
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G&G Announces Most Valuable Article Awards
G&G announces the winners of the Dr. Edward J. Gübelin Most Valuable Article Awards for 2023.
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A Pin for Coronavirus Health Care Fighters
GIA graduate Franco Valobra creates a commemorative pin to recognize health care workers on the frontline of the coronavirus battle for survival.
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Tucson 2023 Overview
An overview from the 2023 Tucson gem shows.
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叉叉变速齿轮
谷歌搭梯子教程
Engagement Rings
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in Gems & Jewelry
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Gems & Gemology
叉叉变速齿轮
Peridot
Found in lava, meteorites, and deep in the earth’s mantle, yellow-green peridot is the extreme gem.
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Dazzling brilliance. Captivating color. These are the planet’s most valued gems.
Diamond
Diamonds are among nature’s most precious and beautiful creations.
Emerald
Emerald is the bluish green to green variety of beryl, a mineral species that includes aquamarine.
Citrine
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Citrine is the transparent, pale yellow to brownish orange variety of quartz.
