mineral

Tumbled amethyst quartz

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron-related defects

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent gray-to-purple color, vitreous luster, hexagonal crystal structure, no cleavage, conchoidal fracture, specific gravity about 2.65. The smooth, rounded surface indicates tumbling or polishing.

Identified August 20, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids fill cavities in volcanic rocks, especially basalt; purple coloration develops through irradiation and iron impurities. Most commercial material formed during relatively young Mesozoic–Cenozoic volcanic episodes.

Uses & applications

Used as a gemstone, ornamental material, crystal specimen, and lapidary rough; tumbled pieces commonly sell as inexpensive décor or metaphysical stones.

Geological facts

Amethyst is quartz’s purple variety and can fade with prolonged heating or strong sunlight. Its color intensity varies with iron content and irradiation history.

Field identification & locations

Identify by its purple hue, glassy luster, conchoidal fracture, and hardness sufficient to scratch ordinary glass; unlike fluorite, it lacks cleavage. Major sources include Brazil, Uruguay, Zambia, and Bolivia.