mineral

Amethyst-bearing quartz cluster

Quartz, SiO₂; purple areas are amethyst, the violet variety of quartz

AI-generated identification · may be incorrect

Hardness 7 Mohs; mostly translucent to milky white with violet patches, vitreous luster, and hexagonal crystal structure. Quartz has no cleavage and commonly breaks with conchoidal fractures.

Identified September 27, 2026More mineral →

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Physical properties

Hardness 7 Mohs; mostly translucent to milky white with violet patches, vitreous luster, and hexagonal crystal structure. Quartz has no cleavage and commonly breaks with conchoidal fractures.

Formation & geological history

Quartz crystallizes from silica-rich fluids in cavities and veins; amethyst’s purple color is caused by trace iron and natural irradiation. Such deposits occur in rocks of many ages, often in volcanic cavities.

Uses & applications

Quartz and amethyst are used for jewelry, ornament, and mineral collecting; quartz also has extensive industrial uses in glass and electronics.

Geological facts

Amethyst color can fade with prolonged heat or strong sunlight.

Field identification & locations

Look for glassy luster, hardness sufficient to scratch glass, and purple coloration within quartz. Amethyst is found worldwide, notably in Brazil, Uruguay, and Zambia; this rough specimen is approximately $5–$30, depending on size and quality.