mineral

Amethyst crystal point

Amethyst, purple quartz (SiO₂)

AI-generated identification · may be incorrect

Mohs hardness 7; purple to violet color from iron and irradiation, vitreous luster, trigonal crystal structure, and no cleavage with conchoidal fracture. The specimen appears translucent, naturally terminated, and possibly lightly polished or included.

Identified August 31, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids or gas cavities in volcanic rocks deposit quartz; color develops through iron impurities and natural radiation. Amethyst commonly formed in volcanic cavities from the Cenozoic to older geological ages.

Uses & applications

Used as a gemstone, ornamental crystal, jewelry, and mineral-collection specimen. Common commercial material is cut, polished, or sold as crystal points and geodes.

Geological facts

Color intensity varies with iron content and heating can turn amethyst yellow, producing citrine. Excessive sunlight may fade some specimens.

Field identification & locations

Identify by purple quartz color, glassy luster, hardness sufficient to scratch glass, and quartz-like conchoidal fracture; common sources include Brazil, Uruguay, Zambia, and Bolivia. Natural points often show six-sided prism faces and termination.