sedimentary

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness of 7 on the Mohs scale, typically translucent to opaque with a waxy to vitreous luster, conchoidal fracture, and no true cleavage. Specific gravity is approximately 2.65.

Identified August 5, 2026More sedimentary →

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Physical properties

Hardness of 7 on the Mohs scale, typically translucent to opaque with a waxy to vitreous luster, conchoidal fracture, and no true cleavage. Specific gravity is approximately 2.65.

Formation & geological history

Formed through the mechanical weathering and erosion of quartz-bearing rocks like granite or quartzite, followed by transportation by water and smoothing via wave or river action over thousands to millions of years.

Uses & applications

Used primarily in landscaping, decorative gravel, aggregate in construction, and as tumbling stones by rockhounds.

Geological facts

Quartz is one of the most abundant minerals in the Earth's continental crust and is exceptionally resistant to chemical weathering, which is why it commonly survives as smooth pebbles on beaches and in riverbeds.

Field identification & locations

Easily identified by its hardness (it will scratch glass), lack of cleavage, and smooth, rounded shape resulting from aqueous transport. Found globally in river gravels, beaches, and alluvial deposits.