mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale. Color: Off-white to translucent milky grey with brownish fractures/veins. Luster: Waxy to vitreous. Crystal structure: Trigonal (microcrystalline/massive in river-worn pebbles). Cleavage: None (conchoidal fracture). Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Luster: Waxy to vitreous

Identified July 23, 2026More mineral →

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Physical properties

Formation & geological history

Formed through hydrothermal deposition or igneous crystallization, then eroded, transported, and rounded by water action in stream beds, river channels, or coastal environments.

Uses & applications

Commonly used as decorative gravel, in landscaping, aquariums, pebble art, and for tumbling/polishing by rockhounds. Pure quartz is used in glassmaking and electronics.

Geological facts

Water-worn quartz pebbles are among the most abundant rocks found along riverbanks and beaches worldwide due to quartz's high resistance to both physical abrasion and chemical weathering.

Field identification & locations

Identified by its hard, scratch-resistant surface (can scratch glass), rounded smooth water-worn texture, and waxy or greasy luster. Found in river beds, beaches, and glacial deposits globally.