mineral

Amethyst cluster

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

AI-generated identification · may be incorrect

Typically Mohs hardness 7, vitreous luster, transparent to translucent purple crystals, and conchoidal fracture; quartz has a trigonal crystal structure and no cleavage. The specimen appears to be a small natural crystal cluster, possibly with pale quartz or calcite matrix.

Identified September 6, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids fill cavities in volcanic rocks, especially basaltic vesicles; growth commonly occurred during the Cenozoic, though deposits vary widely in age. Major sources include Brazil, Uruguay, Zambia, and Mexico.

Uses & applications

Used as a collectible and ornamental gemstone; transparent pieces are cut for jewelry, while clusters are sold as décor and metaphysical specimens. Common small specimens have modest commercial value.

Geological facts

Amethyst’s purple color can fade with prolonged heating or strong sunlight, and heating may produce yellow citrine-like material. Its color zoning and crystal habit are useful diagnostic features.

Field identification & locations

Identify it by six-sided prismatic crystals, pointed terminations, purple color, glassy luster, and inability to scratch with a steel knife but ability to scratch glass. Estimated value: $5–$30 for a small common cluster, or $40–$150+ if exceptionally vivid, large, or well formed.