gemstone
Ruby (mounted cabochon)
Corundum, Al₂O₃; red color typically from chromium
AI-generated identification · may be incorrectRed, translucent to opaque cabochon in a metal setting; Mohs hardness 9, vitreous luster, trigonal crystal structure, no true cleavage. The image does not establish whether it is natural, synthetic, or treated.
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Physical properties
Red, translucent to opaque cabochon in a metal setting; Mohs hardness 9, vitreous luster, trigonal crystal structure, no true cleavage. The image does not establish whether it is natural, synthetic, or treated.
Formation & geological history
Ruby forms when corundum crystallizes in aluminum-rich, silica-poor rocks, including metamorphic marble and some igneous deposits. Geological ages vary by deposit; Burmese marble-hosted rubies are notably ancient.
Uses & applications
Used in jewelry and, for industrial-quality corundum, abrasives and specialized components.
Geological facts
Ruby and sapphire are varieties of the same mineral, corundum; red corundum is called ruby.
Field identification & locations
Look for hardness, vivid red color, and inclusions, but visual inspection cannot reliably confirm authenticity or treatment. Major sources include Myanmar, Mozambique, Sri Lanka, Thailand, and Madagascar; gemological testing is recommended.
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