mineral

Tumbled amethyst

Quartz, SiO₂; purple variety colored mainly by iron impurities and irradiation

AI-generated identification · may be incorrect

Mohs hardness 7; purple to violet, translucent, with a vitreous luster and conchoidal fracture. Trigonal crystal structure; no cleavage; specific gravity about 2.65.

Identified August 13, 2026More mineral →

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Physical properties

Mohs hardness 7; purple to violet, translucent, with a vitreous luster and conchoidal fracture. Trigonal crystal structure; no cleavage; specific gravity about 2.65.

Formation & geological history

Forms when silica-rich hydrothermal fluids fill cavities in volcanic rocks, commonly alongside chalcedony and other quartz varieties. Most deposits formed during relatively young volcanic episodes, especially Mesozoic–Cenozoic basalt provinces.

Uses & applications

Used as an ornamental gemstone, jewelry, carvings, polished specimens, and lapidary material. Tumbled pieces are usually inexpensive and popular for collecting or décor.

Geological facts

The purple color can fade with prolonged heat or strong sunlight. Amethyst is February’s birthstone and is among the most widely recognized quartz varieties.

Field identification & locations

Identify 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 sources include Brazil, Uruguay, Zambia, and Mexico.