mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Tan, brown, and translucent white; Luster: Vitreous to waxy; Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Tan, brown, and translucent white
Luster: Vitreous to waxy

Identified July 21, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Tan, brown, and translucent white; Luster: Vitreous to waxy; Crystal structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Formation & geological history

Forms through the crystallization of silica-rich magma or precipitation from hydrothermal fluids. This specific specimen is a water-worn river pebble, likely millions of years old, shaped by alluvial erosion.

Uses & applications

Used in jewelry as tumbled stones, in industrial glass making, as an abrasive, and widely used in the construction of concrete and road bases.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is chemically and physically resistant to weathering, which is why it often remains as rounded pebbles in riverbeds.

Field identification & locations

Identified in the field by its hardness (it can scratch glass), its lack of cleavage, and its characteristic waxy luster when water-worn. Common in riverbeds, beaches, and glacial deposits worldwide.