mineral

Amethyst

Quartz, SiO₂, purple variety

AI-generated identification · may be incorrect

Mohs hardness 7; vitreous luster; purple coloration from trace iron and irradiation; trigonal crystal structure with indistinct cleavage and conchoidal fracture. The specimens appear to be rough, crystalline fragments, possibly quartz-coated matrix.

Identified August 15, 2026More mineral →

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Physical properties

Formation & geological history

Forms mainly in cavities of volcanic rocks, especially basaltic lava flows, where silica-rich fluids deposit quartz and amethyst over millions of years. Important deposits occur in Brazil, Uruguay, Zambia, and Mexico; ages vary by deposit, commonly Mesozoic to Cenozoic.

Uses & applications

Used as a gemstone, ornamental stone, mineral specimen, and occasionally in carved objects. It is also popular in metaphysical collecting, though healing claims lack scientific support.

Geological facts

Amethyst’s purple color can fade with prolonged heating or intense sunlight; heat treatment may produce yellow citrine. Large geodes from Brazil and Uruguay are especially famous.

Field identification & locations

Identify it by purple color, glassy luster, hardness sufficient to scratch ordinary glass, and six-sided quartz crystals or crystalline fracture. Commonly found in volcanic geodes and hydrothermal veins.