mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: White, milky, or translucent with yellow/red iron staining; Luster: Vitreous to greasy; Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: White, milky, or translucent with yellow/red iron staining
Luster: Vitreous to greasy

Identified April 19, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silicon-rich hydrothermal fluids or within igneous veins. This specific specimen has been rounded by fluvial (water) erosion over long periods, likely in a riverbed or coastal environment. Geological age varies significantly by location.

Uses & applications

Used as abrasive sand, in glass making, as a landscaping stone (river rock), and occasionally as a source of high-purity silicon for electronics. Smooth pebbles are popular in aquarium decor and home crafts.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is colorless, but impurities and microscopic fluid inclusions create the 'milky' white appearance and yellow/orange staining (iron oxide) seen here.

Field identification & locations

Identify in the field by its hardness (it will scratch glass and steel), lack of cleavage, and smooth, water-worn texture. It is ubiquitous in gravel pits, beaches, and creek beds globally.