mineral
Amethyst (rough crystal)
Quartz, SiO₂; purple color commonly caused by iron impurities and natural irradiation
AI-generated identification · may be incorrectMohs hardness 7; translucent purple with a vitreous luster and hexagonal crystal structure. The specimen appears to be a broken or partly terminated crystal; quartz has no true cleavage and typically breaks conchoidally.
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Physical properties
Mohs hardness 7; translucent purple with a vitreous luster and hexagonal crystal structure. The specimen appears to be a broken or partly terminated crystal; quartz has no true cleavage and typically breaks conchoidally.
Formation & geological history
Forms in silica-rich hydrothermal veins and gas cavities in volcanic rocks as quartz crystals grow from mineral-bearing fluids. Amethyst deposits span a wide range of geological ages.
Uses & applications
Used for faceted and cabochon jewelry, beads, ornaments, and mineral collections; lower-grade material is also used decoratively.
Geological facts
Amethyst is the purple variety of quartz, and its color can fade with prolonged exposure to strong sunlight or heat.
Field identification & locations
Look for purple color zoning, glassy luster, and hardness sufficient to scratch ordinary glass; common sources include Brazil, Uruguay, Zambia, and other quartz-bearing regions. The image alone cannot confirm locality or natural versus treated color.
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