mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to tan with waxy surface; Luster: Vitreous to greasy (when weathered); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Milky white to tan with waxy surface
Luster: Vitreous to greasy (when weathered)

Identified January 2, 2026More mineral →

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Physical properties

Formation & geological history

Formed from cooling silica-rich magma or precipitation in hydrothermal veins. This specific specimen is a 'clast' that has been weathered and rounded by water transport in a fluvial (river) environment over thousands of years.

Uses & applications

Used in construction as aggregate, in glass manufacturing, as abrasives, and sometimes tumbled for jewelry or decorative landscaping. High-purity quartz is used in electronics for its piezoelectric properties.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'Quarz' and it was historically believed by some ancient cultures to be 'permanent ice' that would never melt.

Field identification & locations

Identify in the field by its hardness (it will easily scratch glass and steel) and lack of cleavage. This specific water-worn texture is common in riverbeds and glacial deposits globally. It has a distinctive sugary or waxy texture when wet.