mineral

Quartz (Common Milky Quartz Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: White, yellowish-beige, or translucent, Luster: Vitreous to greasy, Crystal structure: Hexagonal (trigonal), Cleavage: None/Conchoidal fracture, Specific gravity: 2.65

Identified May 17, 2026More mineral →

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Physical properties

Formation & geological history

Formed from hydrothermal veins or cooled silica-rich magma. This specimen appears as a river-worn or beach-tumbled pebble, having undergone mechanical weathering and erosion over thousands of years.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, and as decorative gravel or landscaping stone. High-purity quartz is essential for silicon chip manufacturing.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. When rubbed together in the dark, some quartz pebbles exhibit triboluminescence, creating a faint internal glow.

Field identification & locations

Identify by its hardness (it will scratch glass and steel), lack of cleavage, and waxy/vitreous appearance. Common in riverbeds, beaches, and mountain trails worldwide. For collectors, look for clarity or unique inclusions.

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Mineral/Rock

Banded Gneiss (River Rock/Pebble)

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