sedimentary

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale. Color: White to off-white with subtle translucent areas. Luster: Vitreous to greasy. Crystal structure: Trigonal (microcrystalline or massive in this weathered form). Cleavage: None, exhibits conchoidal fracture. Specific gravity: 2.65.

Hardness: 7 on the Mohs scale
Color: White to off-white with subtle translucent areas
Luster: Vitreous to greasy

Identified August 1, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the mechanical and chemical weathering of primary igneous or metamorphic rocks containing quartz. Due to its extreme chemical resistance and high hardness, quartz survives long periods of transport in rivers and shorelines, becoming rounded into pebbles over geological timescales.

Uses & applications

Used in landscaping, decorative stone, road aggregate, and sometimes in lapidary work or as an abrasive.

Geological facts

Quartz is one of the most abundant and durable minerals in the Earth's continental crust. Its high resistance to weathering is why quartz-rich rocks and pebbles outlast almost all other mineral components in sedimentary systems.

Field identification & locations

Easily identified by its hardness (scratches glass), lack of cleavage, and resistance to acid. Commonly found in riverbeds, beaches, and conglomerate sedimentary rock formations worldwide.