mineral

Quartz (Water-worn pebble)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to translucent tan; Luster: Vitreous to waxy (when frosted/worn); Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on Mohs scale
Color: Milky white to translucent tan
Luster: Vitreous to waxy (when frosted/worn)

Identified March 21, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal fluids or within igneous and metamorphic rocks. This specific specimen has been chemically and mechanically weathered, likely in a river or coastal environment, resulting in its smooth, rounded 'pebble' shape.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, and as a filler in construction materials. Common stones like this are also used for lapidary tumbling or as decorative garden mulch.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Historically, quartz pebbles were often used as hearth stones or 'sighting crystals' because of their durability and ability to withstand heat.

Field identification & locations

Identify in the field by its hardness (it can easily scratch glass or steel) and its lack of cleavage planes. Found globally in almost all geological environments, particularly in riverbeds and beaches.