mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Milky white to translucent; Luster: Vitreous (glassy) to dull when weathered; Crystal Structure: Trigonal (often appears massive in river stones); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Milky white to translucent
Luster: Vitreous (glassy) to dull when weathered

Identified March 8, 2026More mineral →

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Physical properties

Formation & geological history

Formed from the crystallization of silica-rich magma or precipitation from hydrothermal veins. This specific specimen has been rounded and smoothed by fluvial (river) or glacial erosion over thousands of years.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, and as decorative river rock in landscaping.

Geological facts

Quartz is one of the most abundant minerals in Earth's crust. Because of its hardness and chemical stability, it survives weathering long after other minerals in a rock have broken down into clay.

Field identification & locations

Identify in the field by its hardness (it will scratch glass) and lack of cleavage (it breaks in irregular, curved flakes). Found globally in riverbeds, beaches, and soil. Collectors often look for clear or uniquely colored variants like amethyst or citrine.