mineral

Amethyst quartz cluster

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by irradiation and iron impurities

AI-generated identification · may be incorrect

Typically Mohs hardness 7, vitreous luster, white-to-purple color, hexagonal/trigonal crystal structure, and indistinct cleavage; specific gravity about 2.65. The specimen appears to be a small, partly matrix-attached crystal cluster with deep violet zoning.

Identified August 17, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids or volcanic gases fill cavities in basalt and other volcanic rocks; crystals commonly developed during Mesozoic–Cenozoic volcanic activity, though ages vary by locality.

Uses & applications

Used as a gemstone, ornamental mineral, lapidary material, and popular collector specimen; commercial amethyst is also used in carvings and decorative geodes.

Geological facts

Purple intensity can fade with prolonged heat or strong sunlight. Amethyst is quartz rather than a separate mineral species, and its color may grade into smoky quartz or citrine.

Field identification & locations

Identify by purple transparent-to-translucent quartz crystals, glassy luster, hardness that scratches glass, and lack of obvious cubic cleavage. Common sources include Brazil, Uruguay, Zambia, Namibia, and Mexico; avoid confusing it with fluorite, which is softer and commonly cubic.