sedimentary

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness of 7 on the Mohs scale, white or off-white color, vitreous to dull 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, white or off-white color, vitreous to dull luster, trigonal crystal system, conchoidal fracture, specific gravity of 2.65.

Formation & geological history

Formed through the mechanical weathering and water transport of larger quartz rocks or veins, typically found in riverbeds, beaches, and alluvial deposits over thousands to millions of years.

Uses & applications

Used in landscaping, decorative gravel, aquariums, and occasionally in abrasive manufacturing or glassmaking if gathered in bulk.

Geological facts

Quartz is one of the most abundant and durable minerals in the Earth's continental crust. Its high resistance to chemical and physical weathering allows it to survive long journeys in river systems, resulting in smooth, rounded pebbles.

Field identification & locations

Can be identified in the field by its high hardness (scratches glass) and lack of reactivity to acid. Common worldwide in almost any gravel bar, stream, or beach.