mineral

Amethyst (rough quartz)

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

AI-generated identification · may be incorrect

Typically violet to purple with a vitreous luster, Mohs hardness 7, no cleavage, and conchoidal fracture; crystals are hexagonal, though this specimen appears massive and rough.

Identified August 24, 2026More mineral →

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Physical properties

Typically violet to purple with a vitreous luster, Mohs hardness 7, no cleavage, and conchoidal fracture; crystals are hexagonal, though this specimen appears massive and rough.

Formation & geological history

Forms mainly in cavities of volcanic basalt when silica-rich hydrothermal fluids deposit quartz; many commercial deposits formed during the Cenozoic, commonly as geodes.

Uses & applications

Used as a gemstone, ornamental material, and mineral specimen; small rough pieces commonly have modest collector value.

Geological facts

Color intensity varies with iron content, irradiation, and heating; heat treatment can produce citrine-like yellow quartz.

Field identification & locations

Identify by purple color, glassy luster, hardness sufficient to scratch glass, and lack of cleavage; common sources include Brazil, Uruguay, Zambia, and Namibia. The image is somewhat blurred, so pale purple quartz is the best identification.