mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: White, tan, or milky; Luster: Vitreous to waxy; Crystal structure: Trigonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: White, tan, or milky
Luster: Vitreous to waxy

Identified April 15, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: White, tan, or milky; Luster: Vitreous to waxy; Crystal structure: Trigonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Formed from the crystallization of silica-rich fluids in veins or igneous environments. These specific specimens are water-worn, having been smoothed by mechanical weathering in a riverbed or coastal environment.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, and as construction aggregate. Smooth pebbles are commonly used in landscaping and aquarium decor.

Geological facts

Quartz is the most abundant mineral in the Earth's continental crust. These rounded shapes indicate the rocks have traveled long distances from their source, losing sharp edges through abrasion.

Field identification & locations

Identify by its hardness (cannot be scratched by a steel knife) and lack of cleavage. Look for the translucent look and smooth, rounded water-worn texture in stream beds or glacial till.