mineral

Tumbled amethyst

Amethyst, purple variety of quartz (SiO₂)

AI-generated identification · may be incorrect

Purple, translucent to opaque, vitreous luster; trigonal crystal structure, Mohs hardness 7, no cleavage, uneven fracture. The pictured piece is rounded and polished.

Identified October 13, 2026More mineral →

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Physical properties

Purple, translucent to opaque, vitreous luster; trigonal crystal structure, Mohs hardness 7, no cleavage, uneven fracture. The pictured piece is rounded and polished.

Formation & geological history

Forms when iron-bearing quartz crystallizes in gas cavities and veins, often in volcanic rocks; amethyst deposits range from ancient to geologically recent.

Uses & applications

Used for jewelry, ornaments, and mineral collecting; tumbled pieces are commonly sold as decorative stones.

Geological facts

Amethyst’s purple color is associated with trace iron and natural irradiation. Heating can turn some amethyst yellow or orange, resembling citrine.

Field identification & locations

Identify by its quartz-like hardness, glassy luster, and purple color; common sources include Brazil, Uruguay, and Zambia. A small tumbled stone like this typically sells for about $2–$10.