mineral

Quartz Pebble

Silicon Dioxide (SiO2)

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

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

Identified June 28, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed from cooling silica-rich magma or precipitation from hydrothermal veins. This specific specimen has been water-worn and rounded by fluvial or coastal erosion processes.

Uses & applications

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

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz gets its cloudy appearance from tiny fluid inclusions of gas or liquid trapped during crystal growth.

Field identification & locations

Identify in the field by its hardness (will scratch glass), absence of cleavage, and smooth, rounded water-worn texture. Commonly found in riverbeds and on beaches worldwide.