sedimentary

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness of 7 on the Mohs scale, typically white to pale yellow or translucent, vitreous to greasy luster, trigonal crystal system, conchoidal fracture, specific gravity of 2.65.

Identified August 2, 2026More sedimentary →

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Physical properties

Hardness of 7 on the Mohs scale, typically white to pale yellow or translucent, vitreous to greasy luster, trigonal crystal system, conchoidal fracture, specific gravity of 2.65.

Formation & geological history

Formed from parent igneous, metamorphic, or sedimentary rocks that underwent weathering and erosion, followed by water transport and mechanical rounding in rivers, streams, or beaches over thousands to millions of years.

Uses & applications

Used in landscaping, decorative gravel, raw material for glassmaking, silicon production, and occasionally in lapidary arts or as tumbled stones.

Geological facts

Quartz is one of the most abundant and durable minerals in Earth's continental crust, highly resistant to both chemical and mechanical weathering, which allows it to survive long transport as pebbles.

Field identification & locations

Easily identified in the field by its high hardness (scratches glass), smooth water-worn shape, and lack of effervescence in acid. Commonly found in riverbeds, beaches, and conglomerate rock formations.