sedimentary

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to light brownish-tan; Luster: Vitreous to waxy/greasy; Crystal Structure: Trigonal (often smooth and rounded by erosion in pebbles); Cleavage: None (conchoidal fracture); Specific Gravity: ~2.65

Hardness: 7 on Mohs scale
Color: Milky white to light brownish-tan
Luster: Vitreous to waxy/greasy

Identified July 26, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the weathering and erosion of quartz-bearing rocks such as granite, quartzite, or sandstone. River currents or ocean waves tumble and smooth the fragment over time into a pebble.

Uses & applications

Stream or river pebbles like this are used decoratively in landscaping, aquariums, crafts, and as aggregate in construction. High-purity quartz pebbles are ground for industrial silica applications.

Geological facts

Quartz is one of the most abundant minerals in Earth's continental crust. Its high hardness and chemical resistance allow it to survive long-term erosion that destroys softer minerals.

Field identification & locations

Identified by its hardness (scratches glass), lack of cleavage, translucent appearance, and rounded shape from aquatic transportation. Commonly found along riverbeds, beaches, and gravel deposits.