Alexandrite
Green in sunlight. Red in lamplight. Color-changing alexandrite is nature’s magic trick.


Explores the application of several machine learning models to complement traditional gem classification approaches.
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The Tokyo laboratory reports on a submitted stone composed of both chrysoberyl and alexandrite.
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An octahedral fluorite crystal is observed in Brazilian alexandrite.
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Pleochroic colors caused by cyclic twinning produce a kaleidoscope effect in alexandrite.
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Examination of alexandrite reveals three phases of matter within a single inclusion suite.
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An overview of the geographic origin complexities facing the gem and jewelry industry today.
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The geographic source of this rare color-change gem has a significant impact on value. Trace element chemistry profiles allow GIA to accurately determine origin for alexandrite from several countries.
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With more than 90 field expeditions on six continents since 2008, GIA has accumulated over 22,000 colored stone reference samples. This extensive collection of colored stones with known origins supports GIA’s research on geographic origin determination.
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GIA’s services and instruments have grown in importance and impact as new gem treatments and laboratory-grown gems enter the market.
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Shows how alexandrite’s color and color change are affected by cut and the orientation of table facets.
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