mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: cloudy gray to white with iron staining, Luster: vitreous to waxy (smooth when wet), Crystal structure: Trigonal (microcrystalline), Cleavage: None/Conchoidal fracture.

Identified June 24, 2026More mineral →

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Physical properties

Formation & geological history

Formed via hydrothermal precipitation in veins or within cooling silica-rich magma; subsequently eroded and rounded by water transport (alluvial processes) over thousands of years.

Uses & applications

Commonly used as abrasive grit, in landscaping, as a source of silica for glass manufacturing, and for decorative use in rock tumbling.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. These smooth shapes are created by the abrasive action of water moving rocks against each other in rivers or beaches.

Field identification & locations

Identify in the field by its hardness (will scratch glass), lacks cleavage planes, and possesses a smooth, water-worn exterior in riverbeds. Found globally in almost all fluvial environments.