mineral

Quartz (River Pebble)

Quartz (Silicon Dioxide, SiO2)

Hardness: 7.0 on Mohs scale. Color: Tan, beige, or milky white with iron staining. Luster: Vitreous to waxy when weathered. Crystal structure: Trigonal/Hexagonal (hidden in water-worn samples). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Hardness: 7
Color: Tan, beige, or milky white with iron staining
Luster: Vitreous to waxy when weathered

Identified April 11, 2026More mineral →

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Physical properties

Formation & geological history

Formed from cooling silica-rich hydrothermal fluids or within igneous and metamorphic rocks. This specific specimen is a 'river pebble,' meaning it has been eroded and smoothed by water transport over long periods, likely originating from a quartz vein.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, and as decorative landscaping gravel. Smooth pebbles are often used in massage therapy or as pocket stones.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'Quarz', which may have Slavic origins meaning 'hard'. It is highly resistant to both chemical and physical weathering.

Field identification & locations

Identify in the field by its hardness (it will scratch glass and steel), its lack of cleavage, and its smooth, rounded 'potato-like' appearance when found in riverbeds or glacial deposits. Common globally in almost every geological environment.

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