mineral

Amethyst (rough chip)

Quartz, purple variety; silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Mohs hardness 7; translucent purple to lilac with vitreous luster, commonly showing white quartz zoning. It has a trigonal crystal structure and indistinct cleavage, with conchoidal fracture and specific gravity around 2.65.

Identified August 19, 2026More mineral →

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Physical properties

Formation & geological history

Forms when trace iron in quartz is irradiated, commonly in gas cavities and fractures of volcanic rocks, especially basaltic lava flows. Most specimens formed during relatively recent volcanic episodes, though deposits range from Paleozoic to Cenozoic age.

Uses & applications

Used as a gemstone, beads, carvings, and mineral specimens; lower-grade material is used for tumbled stones and decorative objects. It has limited industrial value beyond ordinary quartz applications.

Geological facts

Purple color intensity depends on iron content, irradiation, and heating history; heating can turn it yellow-orange, producing citrine. Amethyst is February’s birthstone and the traditional gemstone for the sixth wedding anniversary.

Field identification & locations

Identify it by purple color, glassy luster, hardness sufficient to scratch ordinary glass, and quartz-like conchoidal fracture; the pictured piece appears rough or lightly worn. Common sources include Brazil, Uruguay, Zambia, Bolivia, and Mexico.