mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Tan to milky white with iron staining; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Tan to milky white with iron staining
Luster: Vitreous to waxy

Identified April 1, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Tan to milky white with iron staining; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed from molten silica cooling in igneous veins or as a secondary mineral in metamorphic rocks. This specific specimen is a water-worn river pebble, likely millions of years old, rounded by mechanical erosion in a high-energy aquatic environment.

Uses & applications

Used primarily as decorative landscaping gravel, in the manufacture of glass and ceramics, as an abrasive, and in the production of silicon for electronics.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its piezoelectric properties allow it to be used in watches and electronics to keep precise time.

Field identification & locations

Identify in the field by its hardness (it can scratch glass), lack of cleavage, and translucent appearance. It is exceptionally common in riverbeds, glacial deposits, and beaches globally.