mineral

Milky quartz crystal

Quartz, silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Hardness 7 Mohs; typically white to colorless, translucent, with a vitreous luster and hexagonal crystal structure. Quartz has no cleavage and shows conchoidal fracture; the specimen appears naturally fractured or roughly terminated.

Identified September 7, 2026More mineral →

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Physical properties

Formation & geological history

Forms in silica-rich igneous, metamorphic, and hydrothermal environments as veins or cavity crystals. Quartz is geologically widespread and may range from Precambrian to recent in age.

Uses & applications

Used for glass, ceramics, electronics, abrasives, and engineered stone; attractive transparent pieces are collected or cut as gemstones. This rough specimen is likely worth about $2–$15.

Geological facts

Its cloudy appearance results from microscopic fluid inclusions, fractures, or mineral impurities rather than a different quartz species. Quartz is one of Earth’s most abundant and chemically durable minerals.

Field identification & locations

Identify it by its glassy luster, lack of cleavage, conchoidal fracture, and ability to scratch ordinary glass; it should not fizz in dilute acid. Common localities include Brazil, Madagascar, the United States, and worldwide quartz veins.