Mineral / Sedimentary

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: Translucent white to tan/grey, Luster: Vitreous to waxy (when wet/polished), Crystal Structure: Trigonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified April 12, 2026More mineral / sedimentary →

Explore Quartz Pebble in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 7 (Mohs scale), Color: Translucent white to tan/grey, Luster: Vitreous to waxy (when wet/polished), Crystal Structure: Trigonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Formation & geological history

Formed from the crystallization of silica-rich fluids or the weathering of larger igneous/metamorphic rocks. This specific specimen appears to be a water-worn river pebble, shaped by erosion and transport over millennia.

Uses & applications

River pebbles are used in landscaping, road construction, various industrial glass-making processes (if high purity), and as decorative stones in aquariums.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. This pebble’s rounded shape is a physical record of its journey through a high-energy water environment like a stream or beach.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife (hardness) and its lack of visible cleavage planes; find in riverbeds, gravel pits, and coastal areas.