mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to tan with iron staining; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Milky white to tan with iron staining
Luster: Vitreous to waxy

Identified April 9, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Milky white to tan with iron staining; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed through the crystallization of molten magma or precipitation from hydrothermal veins. This specific specimen is a water-worn river pebble, having been rounded by fluvial erosion over hundreds to thousands of years.

Uses & applications

Used in the manufacture of glass, electronics (piezoelectric crystals), abrasives, and as a decorative landscaping stone.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is extremely chemically and physically stable, which is why it often survives as pebbles long after other minerals have weathered away.

Field identification & locations

Identify in the field by its ability to scratch glass and steel, its lack of cleavage (it breaks in curved surfaces like glass), and its often translucent appearance. Found worldwide in riverbeds and beaches.