gemstone

Tumbled amethyst

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

AI-generated identification · may be incorrect

Mohs hardness 7; translucent lavender-purple color, vitreous luster, hexagonal crystal structure, and indistinct cleavage. The smoothly rounded surface indicates tumbling and polishing.

Identified August 18, 2026More gemstone →

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Physical properties

Mohs hardness 7; translucent lavender-purple color, vitreous luster, hexagonal crystal structure, and indistinct cleavage. The smoothly rounded surface indicates tumbling and polishing.

Formation & geological history

Amethyst forms mainly in gas cavities of volcanic basalt when silica-rich groundwater deposits quartz crystals, commonly during late volcanic stages. The specimen’s exact age and locality cannot be determined from the image.

Uses & applications

Used in inexpensive jewelry, cabochons, ornaments, metaphysical collections, and decorative stonework; it is less valuable than transparent faceted amethyst.

Geological facts

Purple color varies with iron content and heat exposure; heating can turn amethyst yellow or orange, producing citrine-like material. Amethyst is February’s birthstone.

Field identification & locations

Identify it by purple quartz color, glassy luster, hardness, and lack of obvious cleavage; it should scratch glass but not be scratched by a steel knife. Major sources include Brazil, Uruguay, Zambia, and Bolivia.