mineral

Tumbled amethyst

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

AI-generated identification · may be incorrect

Mohs hardness 7; translucent violet to lavender with white quartz areas, vitreous luster, hexagonal crystal structure, and no prominent cleavage. The rounded surface indicates mechanical tumbling and polishing.

Identified August 11, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater deposits quartz in volcanic gas cavities, commonly with iron-bearing impurities; most deposits are Phanerozoic in age. Major sources include Brazil, Uruguay, Zambia, and Bolivia.

Uses & applications

Used as an ornamental stone, jewelry, carvings, meditation objects, and mineral specimens. This small polished piece has modest commercial value.

Geological facts

Amethyst is the traditional February birthstone and the purple variety of quartz. Heating can change its color to yellow-orange citrine or produce ametrine in naturally zoned material.

Field identification & locations

Identify it by its purple color, glassy luster, hardness, and lack of obvious cleavage; it should scratch glass but not be scratched by a steel knife. Common localities include Brazilian and Uruguayan basalt geodes.