sedimentary

Quartz Pebble

Crystalline Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale. Color: Translucent white to milky tan. Luster: Vitreous to waxy. Structure: Hexagonal (trigonal) crystal system, though rounded by erosion. Cleavage: None (conchoidal fracture).

Hardness: 7 on the Mohs scale
Color: Translucent white to milky tan
Luster: Vitreous to waxy

Identified July 7, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed originally in hydrothermal veins or igneous rocks, then weathered, transported by water (rivers or beaches), and rounded over time through abrasion against other rocks. Can be millions of years old.

Uses & applications

Commonly used as decorative landscaping gravel, in construction as aggregate, and sometimes collected as river stones or used in rock tumbling.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. These rounded pebbles are often called 'river rocks' when found in fluvial environments and are indicators of high-energy water transport.

Field identification & locations

Identified in the field by its hardness (it will scratch glass and steel), lack of cleavage, and translucent appearance. Found worldwide in riverbeds, glacial deposits, and beaches.