Mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Tan, white, and translucent; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (trigonal); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

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

Identified March 14, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Tan, white, and translucent; Luster: Vitreous to waxy; Crystal Structure: Hexagonal (trigonal); Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

Formation & geological history

Formed through crystallization from magma or precipitation from hydrothermal veins. The rounded shape indicates secondary weathering in a high-energy fluvial (river) or coastal environment, likely over thousands of years.

Uses & applications

Primary source of silica for glass making, electronics (piezoelectric properties), abrasives, and as decorative aggregate in landscaping or construction.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'Quarz', which had its origins in the Slavic 'twardy' meaning hard. This specific specimen is a 'clast', shaped by the process of saltation in riverbeds.

Field identification & locations

Identify in the field by its ability to scratch glass and its lack of cleavage. This specimen shows 'rinding' or a weathered exterior. Common world-wide in river beds and beaches. Collectors search for these as 'pocket stones' or for rock tumbling.