mineral

Tumbled amethyst

Amethyst, purple quartz (SiO₂)

AI-generated identification · may be incorrect

Mohs hardness 7; purple translucent color from trace iron and irradiation, with vitreous luster and hexagonal quartz structure. It has indistinct cleavage, conchoidal fracture, and specific gravity near 2.65.

Identified August 26, 2026More mineral →

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Physical properties

Formation & geological history

Forms when iron-bearing quartz crystallizes in gas cavities and fractures of volcanic rocks, especially basaltic geodes; most deposits are Mesozoic to Cenozoic, though quartz is far older. This specimen has been polished/tumbled.

Uses & applications

Used as an ornamental stone, cabochon, jewelry gem, geode lining, and inexpensive collectible. It is also marketed decoratively and metaphysically, without established scientific healing effects.

Geological facts

Amethyst’s color ranges from lilac to deep violet and can fade with prolonged heat or sunlight. It is the purple variety of quartz and is February’s birthstone.

Field identification & locations

Identify it by its purple color, glassy luster, hardness, and lack of visible cubic cleavage; glass commonly shows bubbles and is softer. Common sources include Brazil, Uruguay, Zambia, and Bolivia.