mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Off-white, tan, or milky; Luster: Vitreous to greasy; Crystal Structure: Trigonal (often massive in pebbles); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Off-white, tan, or milky
Luster: Vitreous to greasy

Identified July 5, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Off-white, tan, or milky; Luster: Vitreous to greasy; Crystal Structure: Trigonal (often massive in pebbles); Specific Gravity: 2.65

Formation & geological history

Formed from cooling magma or hydrothermal veins, later eroded and rounded by water transport in rivers or beaches. These common pebbles can range from millions to billions of years old.

Uses & applications

Commonly used in landscaping, as aggregate in construction and concrete, and as a source of silica for glass manufacturing.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its durability allows it to survive long periods of erosion, which is why it is the primary component of most river gravel and beach sand.

Field identification & locations

Identified by its ability to scratch glass and its lack of cleavage (it breaks with a conchoidal fracture). It is found globally in almost all geological environments.