mineral

Amethyst cluster

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

AI-generated identification · may be incorrect

Mohs hardness 7; translucent purple crystals with vitreous luster, hexagonal crystal structure, and no true cleavage (conchoidal fracture). Likely formed on a gray or white quartz matrix; specific gravity is about 2.65.

Identified August 16, 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 long periods. Individual deposits commonly range from Mesozoic to Cenozoic age.

Uses & applications

Used as a decorative specimen, lapidary material, and gemstone; fine transparent material is faceted, while clusters are popular for display and metaphysical collecting.

Geological facts

Color intensity depends on iron content and irradiation and may fade with prolonged heat or strong sunlight. Amethyst is the February birthstone and a variety of macrocrystalline quartz.

Field identification & locations

Identify it by purple hexagonal crystals, glassy luster, hardness sufficient to scratch ordinary glass, and quartz-like fracture; common sources include Brazil, Uruguay, Zambia, and Mexico. This specimen appears to be a natural crystal cluster, possibly with smoky or milky quartz.