mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Smoky brown to tan with white milky patches; Luster: Vitreous to greasy; Crystal Structure: Hexagonal (trigonal); Cleavage: Indistinct/Conchoidal fracture; Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Smoky brown to tan with white milky patches
Luster: Vitreous to greasy

Identified July 19, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal fluids or within igneous and metamorphic rocks. This specific specimen is a water-worn river pebble, shaped by erosion over years of transport in water environments.

Uses & applications

Commonly used as a decorative ground cover, in construction aggregate, as a source for silicon in semiconductors, and occasionally as a low-cost lapidary material.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Because of its hardness and chemical stability, it often survives long after the surrounding rock has weathered away.

Field identification & locations

Identify by its inability to be scratched by a steel knife and its lack of clear cleavage. It is found globally in riverbeds, beaches, and soil. Collectors look for clarity or unique inclusions within these pebbles.