mineral

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 (Mohs scale). Color: Tan, brown, or milky white. Luster: Dull to vitreous. Crystal structure: Trigonal/Hexagonal. Specific gravity: 2.65.

Hardness: 7 (Mohs scale)
Color: Tan, brown, or milky white
Luster: Dull to vitreous

Identified June 23, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale). Color: Tan, brown, or milky white. Luster: Dull to vitreous. Crystal structure: Trigonal/Hexagonal. Specific gravity: 2.65.

Formation & geological history

Forms through the crystallization of magma or silica-rich hydrothermal fluids. This specific specimen is a water-worn pebble likely eroded from a vein and polished by river or glacial transport over millions of years.

Uses & applications

Used in construction as aggregate, in glassmaking, and as an abrasive. Smooth pebbles are often used in decorative landscaping and aquariums.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is chemically very stable, which is why it remains as pebbles long after other minerals have weathered away.

Field identification & locations

Identify in the field by its hardness (it can scratch glass) and lack of cleavage. Commonly found in riverbeds, beaches, and gravel pits across the globe.