mineral

Amethyst-bearing quartz

Quartz, silicon dioxide (SiO₂), purple variety amethyst

AI-generated identification · may be incorrect

Mohs hardness 7; translucent purple and colorless zoning, vitreous luster, and conchoidal fracture. It has trigonal crystal structure and no true cleavage; purple color comes mainly from iron impurities and irradiation.

Identified August 15, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids fill cavities in volcanic rocks, especially basalt, where quartz crystals grow over millions of years. The pictured piece appears to be rough, partially crystalline amethyst with milky quartz.

Uses & applications

Used for jewelry, carvings, ornamental stone, and mineral collecting; fine crystals may be geodes or display specimens. Common rough pieces have modest commercial value.

Geological facts

Amethyst is the purple quartz variety and is February’s birthstone. Heating can produce yellow-orange citrine, though natural and treated colors may differ.

Field identification & locations

Identify it by purple zoning, glassy luster, hardness sufficient to scratch glass, and quartz-like fracture; it commonly occurs in Brazil, Uruguay, Zambia, and Mexico. Avoid prolonged strong sunlight, which can fade the color.