mineral

Amethyst quartz cluster

Quartz, SiO₂; purple coloration from iron impurities and irradiation

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent violet-to-lilac crystals with vitreous luster, hexagonal crystal structure, and indistinct cleavage. The specimen appears to include a grayish chalcedony or quartz matrix and iron staining.

Identified August 10, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich hydrothermal fluids fill cavities in volcanic rocks, especially basalt; purple quartz crystals grow inward over long periods, commonly during the Cenozoic or older volcanic episodes.

Uses & applications

Used as a gemstone, ornamental crystal, lapidary material, and mineral-collecting specimen; large decorative clusters are popular in home display.

Geological facts

Amethyst is the purple variety of quartz and is February’s birthstone. Its color can fade with prolonged sunlight or heating, and heat treatment may produce yellow citrine-like material.

Field identification & locations

Identify by its purple color, glassy luster, conchoidal fracture, hexagonal points, and inability to scratch with a steel knife; it should scratch ordinary glass. Common sources include Brazil, Uruguay, Zambia, and Mexico.