mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Brownish-tan to translucent; Luster: Vitreous to waxy (when water-worn); Crystal Structure: Hexagonal (trigonal); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Brownish-tan to translucent
Luster: Vitreous to waxy (when water-worn)

Identified March 9, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. This specific specimen is a 'clast' that has been eroded from its parent rock and rounded by water transport in a river or coastal environment.

Uses & applications

Common quartz is used in glassmaking, abrasives, and as a component in concrete and mortar. Smooth pebbles are often used in landscaping or as decorative stones in aquariums.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Because it is chemically stable and physically hard, it persists as pebbles and sand long after other minerals have weathered away.

Field identification & locations

Identify by its ability to scratch glass and its lack of cleavage. Look for the 'sugary' or glassy texture on broken surfaces. Found globally in riverbeds, beaches, and glacial till. Collectors value them for tumbling.