mineral

Amethyst-bearing quartz cluster

Quartz, SiO₂; purple coloration from irradiation and trace iron

AI-generated identification · may be incorrect

Hardness 7 Mohs; vitreous luster; translucent gray-to-purple crystals with conchoidal fracture and no cleavage. Crystals are trigonal, commonly forming hexagonal prisms with pyramidal terminations; specific gravity is about 2.65.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids or groundwater deposit quartz in cavities and fractures, often in volcanic rocks; purple amethyst commonly develops during late-stage oxidation. Most specimens formed over millions of years, commonly in Cretaceous-to-Cenozoic volcanic provinces.

Uses & applications

Used as a gemstone, ornamental cluster, spiritual/collector material, and source of silica; quality faceted amethyst is used in jewelry, while clusters are decorative.

Geological facts

Purple intensity varies with iron content, irradiation, and heating; excessive heat can turn amethyst yellow or orange, producing citrine-like material.

Field identification & locations

Identify by purple quartz crystals, glassy luster, hardness sufficient to scratch ordinary glass, and lack of cleavage; common sources include Brazil, Uruguay, Zambia, and Mexico. The specimen appears to be a small rough cluster, possibly with colorless quartz and minor host rock.