mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Milky white to translucent grey; Luster: Vitreous to waxy (when water-worn); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture).

Hardness: 7 (Mohs scale)
Color: Milky white to translucent grey
Luster: Vitreous to waxy (when water-worn)

Identified July 12, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Milky white to translucent grey; Luster: Vitreous to waxy (when water-worn); Crystal Structure: Hexagonal (trigonal); Cleavage: None (conchoidal fracture).

Formation & geological history

Formed from cooling magma (igneous) or silica-rich hydrothermal veins. This specific specimen has been Rounded through mechanical weathering in a river or beach environment over months to years.

Uses & applications

Raw quartz is used in glassmaking, abrasives, and electronics (piezoelectric). Tumbled pebbles are used in landscaping, aquariums, and decorative stone crafts.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Because of its high hardness and chemical stability, it survives long journeys down rivers where softer minerals break down into clay.

Field identification & locations

Identify in the field by its ability to scratch glass and lack of cleavage. Look for smooth, rounded pebbles in stream beds, gravel pits, and coastal areas worldwide.