Alexandrite Gemstone | Natural Alexandrite Stone - GIA
Often described by gem aficionados as “emerald by day, ruby by night,” alexandrite is the very rare color-change variety of the mineral chrysoberyl. Originally discovered in Russia’s Ural Mountains in the 1830s, it’s now found in Sri Lanka, East Africa, and Brazil, but fine material is exceptionally rare and valuable.
Alexandrite Gemstone | Natural Alexandrite Stone - GIA
Alexandrite Gemstone is a rare variety of the mineral Chrysoberyl & is a strongly pleochroic gem. Color-changing alexandrite is nature’s magic trick.
Alexandrite Gemstone | Natural Alexandrite Stone - GIA
Alexandrite Gemstone is a rare variety of the mineral Chrysoberyl & is a strongly pleochroic gem. Color-changing alexandrite is nature’s magic trick.
Alexandrite Description - GIA
Alexandrite, with its chameleon-like qualities, is a rare variety of the mineral chrysoberyl. Its color can be a lovely green in daylight or fluorescent light, changing to brownish or purplish red in the incandescent light from a lamp or candle flame.
Alexandrite History and Lore - GIA
Abundant alexandrite deposits were first discovered in 1830 in Russia’s Ural Mountains. Those first alexandrites were of very fine quality and displayed vivid hues and dramatic color change. The gem was named after the young Alexander II, heir apparent to the throne.
Geographic Origin Determination of Alexandrite
2020年1月31日 · 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.
Alexandrite Gemstone | Natural Alexandrite Stone - GIA
Alexandrite Gemstone is a rare variety of the mineral Chrysoberyl & is a strongly pleochroic gem. Color-changing alexandrite is nature’s magic trick.
Alexandrite Quality Factors - GIA
Alexandrite tends to contain few inclusions. There’s a dramatic rise in value for clean material with good color change and strong colors. A high clarity rating raises the value of alexandrite, especially one with nice color change like this green to red-purple example.
Classification of Gem Materials Using Machine Learning
This study examines the application of several machine learning models to gemstone classification problems involving natural alexandrite, laboratory-grown diamonds, and natural saltwater pearls.
including alexandrite (Leung et al., 1983). In most instances, characteristic inclusions serve to distinguish between natural and synthetic alexandrites (see references above). The natural gemstones usually contain distinctive natural- appearing inclusions such as: ultra-fine parallel growth tubes or needles; solid crystal inclusions of
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