Mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Milky white to off-white; Luster: Vitreous to waxy (when weathered); Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Milky white to off-white
Luster: Vitreous to waxy (when weathered)

Identified March 20, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Milky white to off-white; Luster: Vitreous to waxy (when weathered); Crystal structure: Trigonal/Hexagonal; Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Formed through the cooling of magma or precipitation from hydrothermal veins. This specific specimen has been smoothed and rounded by the abrasive action of water (fluvial erosion) over thousands of years.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, and as decorative landscaping stone or gravel in construction.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'quarz', which has Slavic origins meaning 'hard'.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife and its lack of cleavage. Common in riverbeds, beaches, and soil worldwide. Collectors should look for unique translucency or inclusions within the stone.