mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to translucent yellowish; Luster: Vitreous (glassy) when fresh, waxy or dull when weathered; Crystal Structure: Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Milky white to translucent yellowish
Luster: Vitreous (glassy) when fresh, waxy or dull when weathered

Identified April 4, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the crystallization of silica-rich magma or from hydrothermal veins. This specific specimen is a water-worn river pebble, likely transported and eroded over thousands of years in a fluvial environment.

Uses & applications

Industrial use as an abrasive, in glassmaking, and electronics (as piezoelectric crystals). As a pebble, it is used for landscaping, construction aggregate, and lapidary tumbling.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is highly resistant to both chemical and physical weathering, which is why it often remains as small, rounded pebbles long after other minerals have decomposed into clay.

Field identification & locations

Identify in the field by its inability to be scratched by a steel pocket knife (hardness) and its lack of cleavage. It is commonly found in riverbeds, beaches, and glaciated regions globally.