mineral

River Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale; Color: Milky white, tan, and yellowish-brown; Luster: Vitreous to waxy (when weathered); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Milky white, tan, and yellowish-brown
Luster: Vitreous to waxy (when weathered)

Identified May 21, 2026More mineral →

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Physical properties

Formation & geological history

Formed through crystallization of silica-rich magma or hydrothermal veins. This specific specimen is a water-worn river pebble, likely millions of years old, weathered and smoothed by mechanical erosion in a stream or river bed.

Uses & applications

Used in construction as aggregate, in the manufacture of glass and ceramics, and as a common material for lapidary tumbling and beginner stone collections.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'Quarz', which has roots in Slavic meaning 'hard'. It is chemically and physically resistant to weathering, which is why it often remains as pebbles after other minerals have dissolved.

Field identification & locations

Identify in the field by its hardness (it can scratch glass), lack of cleavage, and translucent appearance. It is commonly found in gravel pits, riverbeds, and beaches worldwide.