Quartz (River Pebble)

Physical Properties

Hardness: 7 (Mohs scale), Color: transclucent white to tan, Luster: vitreous to waxy, Crystal Structure: hexagonal, Cleavage: none (conchoidal fracture), Specific Gravity: 2.65

Formation & Geological History

Formed through the cooling of magma or precipitation from hydrothermal veins. This specific specimen is a water-worn pebble, likely millions of years old, shaped by fluvial erosion in a river or stream bed.

Uses & Applications

Quartz is used in glassmaking, electronics (piezoelectric properties), abrasives, and as a component in concrete and mortar. Smooth pebbles are used in landscaping and aquariums.

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 once believed by ancient Greeks to be ice that had frozen so hard it would never melt.

Field Identification & Locations

Identify by its hardness (it will scratch glass) and lack of cleavage. Look for smooth, rounded shapes in riverbeds, beaches, and gravel pits. It is omnipresent globally.

Identified on: 4/25/2026

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