mineral

Tumbled amethyst

Quartz, purple variety; SiO₂

AI-generated identification · may be incorrect

Typically purple to lilac with white quartz zoning, vitreous luster, and crystalline quartz structure; hardness 7 Mohs, no cleavage, conchoidal fracture, and specific gravity about 2.65. The rounded surface indicates tumbling and polishing.

Identified September 16, 2026More mineral →

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Physical properties

Formation & geological history

Amethyst forms when iron-bearing quartz crystallizes in gas cavities and fractures of volcanic rocks, commonly basalt, followed by irradiation and heat-related color development. Most deposits formed during the Cenozoic or older volcanic episodes, depending on locality.

Uses & applications

Used as an ornamental gemstone, jewelry, carvings, mineral specimens, and metaphysical décor. Tumbled pieces are inexpensive collectibles.

Geological facts

Color intensity depends mainly on iron impurities and irradiation; heating can turn some amethyst yellow, producing citrine. Amethyst is February’s birthstone.

Field identification & locations

Identify it by purple quartz coloration, glassy luster, hardness sufficient to scratch ordinary glass, and lack of cleavage; glass or fluorite may imitate it. Major sources include Brazil, Uruguay, Zambia, and Mexico.