mineral
Amethyst cluster
Amethyst, purple variety of quartz (SiO₂); trigonal crystal system
AI-generated identification · may be incorrectMohs hardness 7; translucent purple crystals with vitreous luster, typically hexagonal prisms and no cleavage. The specimen appears to be a druzy cluster on matrix.
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Physical properties
Mohs hardness 7; translucent purple crystals with vitreous luster, typically hexagonal prisms and no cleavage. The specimen appears to be a druzy cluster on matrix.
Formation & geological history
Forms when silica-rich fluids deposit quartz in cavities and geodes, with trace iron and natural irradiation producing purple color. Amethyst deposits span many geological ages and commonly occur in volcanic rocks.
Uses & applications
Used in jewelry, carvings, décor, and mineral collections.
Geological facts
Amethyst’s color can fade with prolonged exposure to strong sunlight or heat.
Field identification & locations
Identify by purple, glassy quartz crystals that scratch glass and lack cleavage; common sources include Brazil, Uruguay, Zambia, and Madagascar. This small cluster is likely worth about $10–$40 USD, depending on size, color, and crystal quality.
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