mineral

Quartz (River Pebble)

Quartz (Silicon Dioxide - SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to translucent with iron staining (pinkish-orange spot); Luster: Vitreous to waxy (tumbled); Crystal Structure: Hexagonal (trigonal); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Luster: Vitreous to waxy (tumbled)

Identified March 12, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal fluids or within igneous and metamorphic rocks. This specific specimen is a water-worn 'pebble' shaped by fluvial erosion over hundreds to thousands of years in a river or creek bed.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), and as aggregates in construction. Polished pebbles are common in landscaping and as 'worry stones' for collectors.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. River quartz pebbles like this often display 'crescentic impacts' or tiny chatter marks on the surface from hitting other rocks in the current.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife (7 hardness) and its translucent nature when held to light. Found globally in riverbanks, beaches, and glacial till. Common in Appalachian and Rocky Mountain stream beds.

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