mineral

Amethyst quartz cluster

Quartz, SiO₂; purple color caused mainly by iron-related defects and irradiation

AI-generated identification · may be incorrect

Hardness 7 Mohs; vitreous luster; purple quartz crystals with conchoidal fracture and indistinct cleavage. Specific gravity is about 2.65; crystals are typically hexagonal (trigonal symmetry).

Identified August 9, 2026More mineral →

Explore Amethyst quartz cluster in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness 7 Mohs; vitreous luster; purple quartz crystals with conchoidal fracture and indistinct cleavage. Specific gravity is about 2.65; crystals are typically hexagonal (trigonal symmetry).

Formation & geological history

Forms when silica-rich hydrothermal fluids fill cavities in volcanic rocks, where quartz crystals grow over geologic time, commonly from the Cenozoic to older volcanic episodes. The specimen appears to be a natural crystal cluster, possibly with minor matrix.

Uses & applications

Used as a gemstone, ornamental mineral, crystal specimen, and occasionally in carvings; large vivid clusters have strong collector appeal.

Geological facts

Amethyst is the purple variety of quartz and is February’s birthstone. Heating can turn it yellow-orange, producing citrine-like material.

Field identification & locations

Identify by its purple color, glassy luster, hexagonal crystal faces, and hardness sufficient to scratch ordinary glass; avoid prolonged sunlight, which may fade color. Common sources include Brazil, Uruguay, Zambia, Namibia, and Mexico.