sedimentary

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale. Color: White to off-white with minor pinkish or yellowish hues due to impurities. Luster: Vitreous to dull when weathered. Crystal structure: Trigonal. Cleavage: None, exhibits conchoidal fracture. Specific gravity: 2.65.

Hardness: 7 on the Mohs scale
Luster: Vitreous to dull when weathered

Identified August 5, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the physical and chemical weathering of primary rocks like granite or pegmatite. Quartz is exceptionally resistant to weathering, allowing the grains to survive prolonged transport in rivers or ocean waves, eventually becoming rounded pebbles in sedimentary environments over millions of years.

Uses & applications

Used in landscaping, decorative gravel, construction aggregate, and as a raw material for silicon and glass production. Tumbled and polished varieties are also used in lapidary arts and jewelry.

Geological facts

Quartz is one of the most abundant and durable minerals on Earth's continental crust. Because of its resistance to both chemical weathering and mechanical abrasion, quartz pebbles are ubiquitous in riverbeds and beaches worldwide.

Field identification & locations

Easily identified in the field by its high hardness (it will scratch glass and steel), lack of cleavage, and conchoidal fracture. Found globally in stream beds, gravel bars, and sedimentary deposits.