Rock Identifier
Quartz Pebble (Silicon Dioxide (SiO2)) — sedimentary
sedimentary

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness of 7 on the Mohs scale, typically white, gray, or translucent, vitreous luster, hexagonal crystal system when formed well, conchoidal fracture with no true cleavage, specific gravity of 2.65.

Identified More sedimentary
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Physical properties

Hardness of 7 on the Mohs scale, typically white, gray, or translucent, vitreous luster, hexagonal crystal system when formed well, conchoidal fracture with no true cleavage, specific gravity of 2.65.

Formation & geological history

Formed through the weathering and erosion of parent igneous or metamorphic rocks, followed by transport and rounding in riverbeds or marine environments over millions of years.

Uses & applications

Used in landscaping, decorative stone, construction aggregate, and occasionally in lapidary work.

Geological facts

Quartz is one of the most abundant minerals in Earth's continental crust and is exceptionally resistant to weathering, which is why it often survives as rounded pebbles in rivers and beaches long after other minerals have broken down.

Field identification & locations

Can be identified in the field by its high hardness (scratches glass), lack of cleavage, and resistance to acid. Found worldwide in stream beds, beaches, and conglomeratic rock formations.