Rock Identifier
Amethyst crystal cluster (Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation) — mineral
mineral

Amethyst crystal cluster

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

AI-generated identification · may be incorrect

Hardness 7 Mohs; vitreous luster; purple translucent crystals with hexagonal prismatic/trigonal structure and conchoidal fracture, lacking cleavage. Specific gravity is about 2.65.

Identified More mineral
Explore Amethyst crystal cluster in the encyclopedia →

Identify your own rocks.

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

Physical properties

Hardness 7 Mohs; vitreous luster; purple translucent crystals with hexagonal prismatic/trigonal structure and conchoidal fracture, lacking cleavage. Specific gravity is about 2.65.

Formation & geological history

Forms when silica-rich hydrothermal fluids or groundwater fill cavities in volcanic rocks, especially basaltic geodes; many deposits formed during the Cenozoic, though ages vary by locality.

Uses & applications

Used as a gemstone, ornamental specimen, and lapidary material; lower-grade material is used for carvings, polished pieces, and metaphysical décor.

Geological facts

The color can fade with prolonged heat or strong sunlight; natural amethyst commonly grades from pale lilac to deep violet, with crystal tips often showing color zoning.

Field identification & locations

Identify it by purple quartz crystals, glassy luster, and hardness sufficient to scratch ordinary glass; common sources include Brazil, Uruguay, Zambia, and Mexico. The pictured piece appears to be a natural drusy cluster on dark matrix.