mineral

Amethyst crystal fragment

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent purple to violet with a gray-white fractured area, vitreous luster, trigonal crystal structure, and no true cleavage. Specific gravity is about 2.65.

Identified September 13, 2026More mineral →

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Physical properties

Hardness 7 Mohs; translucent purple to violet with a gray-white fractured area, vitreous luster, trigonal crystal structure, and no true cleavage. Specific gravity is about 2.65.

Formation & geological history

Forms in silica-rich hydrothermal fluids filling cavities and fractures in volcanic rocks, especially basaltic geodes; most specimens formed during relatively young volcanic episodes, commonly Cenozoic or older depending on locality.

Uses & applications

Used as a gemstone, ornamental material, and mineral specimen; small rough fragments typically have modest commercial value.

Geological facts

Purple color intensity varies with iron content, irradiation, and heating; heating can produce yellow citrine or reddish-brown tones.

Field identification & locations

Identify by its purple color, glassy luster, conchoidal fracture, hexagonal crystal habits, and ability to scratch glass; common sources include Brazil, Uruguay, Zambia, and Mexico.