Chrysoberyl
“Cat's eyes and color changers”
Chrysoberyl is a beryllium aluminum oxide mineral that produces two extraordinary gem varieties: chatoyant chrysoberyl (cat's eye) and alexandrite, which changes color from green in daylight to red under incandescent light. Despite sharing 'beryl' in its name, it's chemically unrelated to the beryl mineral group.
beryllium aluminum oxide (BeAl₂O₄)
Sri Lanka (cat's eye), Ural Mountains (Russia — alexandrite), Minas Gerais (Brazil), Tanzania, Madagascar
8.5
Fine alexandrite can be more valuable per carat than diamond, ruby, or emerald — a top-quality stone showing vivid green-to-red color change can exceed $70,000 per carat at auction.
Test Your Knowledge
What causes the dramatic color change in alexandrite from green in daylight to red in incandescent light?
Related Specimens
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