mineral

Quartz crystal

Quartz (silicon dioxide, SiO₂), likely milky or drusy quartz

AI-generated identification · may be incorrect

Hardness 7 Mohs; white to translucent with a glassy-to-waxy luster and typically hexagonal crystal structure. It has indistinct cleavage, conchoidal fracture, and specific gravity around 2.65; dark material may be matrix or iron/manganese staining.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich hydrothermal fluids, pegmatites, and cavities in volcanic rocks, commonly during late-stage mineral formation. Its exact geological age and locality cannot be determined from the photograph.

Uses & applications

Common quartz is used in glass, ceramics, abrasives, electronics, and construction; attractive crystals are sold as mineral specimens or used ornamentally. This rough piece has modest commercial value.

Geological facts

The pointed termination and six-sided form are characteristic of quartz, though the specimen appears fractured and partly embedded in dark matrix. Quartz is one of Earth’s most abundant minerals and is resistant to weathering.

Field identification & locations

Look for a glassy luster, conchoidal fracture, hexagonal habit, and inability to scratch with a steel knife; it should scratch ordinary glass. Common sources include Brazil, Madagascar, the United States, and China.