sedimentary

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness of 7 on the Mohs scale, typically white, milky, clear, or brownish, vitreous to greasy luster, trigonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65.

Identified August 3, 2026More sedimentary →

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Physical properties

Hardness of 7 on the Mohs scale, typically white, milky, clear, or brownish, vitreous to greasy luster, trigonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65.

Formation & geological history

Formed through the weathering and erosion of parent rocks containing quartz (such as granite or quartzite). Over millions of years, water action in rivers, streams, or ocean surf rounds the quartz fragments into smooth pebbles.

Uses & applications

Used in landscaping, decorative stone, construction aggregates, glass manufacturing, and abrasive grit.

Geological facts

Quartz is one of the most abundant and durable minerals in Earth's continental crust. Because of its high resistance to chemical weathering and high hardness, quartz survives long transport cycles where other minerals wear away.

Field identification & locations

Easily identified in the field by its high hardness (scratches glass), lack of cleavage, and smooth water-worn shape. Found globally in riverbeds, beaches, and glacial deposits.