mineral

Rough amethyst-bearing quartz specimens

Quartz, SiO₂; purple coloration from trace iron and irradiation

AI-generated identification · may be incorrect

Typically Mohs hardness 7, vitreous luster, conchoidal fracture, no cleavage, and hexagonal crystal structure. The pieces show pale violet amethyst mixed with white/gray quartz and brown iron-oxide staining in a granular host rock.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

Amethyst forms when silica-rich hydrothermal fluids fill cavities or fractures in volcanic rocks, commonly basalt or rhyolite; iron impurities create the purple color. Individual deposits may range from young volcanic settings to geologically ancient Precambrian terrains.

Uses & applications

Used as a jewelry and ornamental gemstone, crystal-collecting specimen, and decorative material; lower-grade material is often tumbled or carved.

Geological facts

Color intensity depends on iron content, irradiation, and heating; excessive heat can turn amethyst yellow or brown, producing citrine-like material.

Field identification & locations

Commonly found in Brazil, Uruguay, Zambia, Namibia, Mexico, and the United States. Identify it by purple quartz color, glassy luster, hardness sufficient to scratch glass, and lack of cleavage; exact locality requires testing or labels.