mineral
Amethyst cluster
Quartz, purple variety; silicon dioxide (SiO₂) colored mainly by iron-related defects and irradiation
AI-generated identification · may be incorrectTypically Mohs hardness 7, vitreous luster, hexagonal crystal structure, conchoidal fracture, and no cleavage; purple quartz crystals occur on a white-to-brown drusy or matrix coating, as shown.
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Physical properties
Typically Mohs hardness 7, vitreous luster, hexagonal crystal structure, conchoidal fracture, and no cleavage; purple quartz crystals occur on a white-to-brown drusy or matrix coating, as shown.
Formation & geological history
Forms when silica-rich hydrothermal fluids fill cavities in volcanic rocks, especially basaltic vesicles; crystals commonly grew during the Cenozoic, though ages vary by deposit.
Uses & applications
Used as a collectible mineral, ornamental specimen, and gemstone; fine transparent crystals may be faceted, while clusters are sold for display and metaphysical markets.
Geological facts
Amethyst’s purple color can fade with prolonged heat or strong sunlight and may turn yellow-orange when heated, producing citrine-like material.
Field identification & locations
Identify it by purple, glassy, six-sided quartz crystals on a cavity matrix; common sources include Brazil, Uruguay, Zambia, Namibia, and Mexico. The image most likely shows natural amethyst on host rock.
