mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: Colorless to milky white; Luster: Vitreous (glassy) to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Colorless to milky white
Luster: Vitreous (glassy) to waxy

Identified July 7, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Colorless to milky white; Luster: Vitreous (glassy) to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed from cooling magma or hydroelectric activity. This specific specimen has been rounded and smoothed by water erosion through river or alluvial transport over thousands of years.

Uses & applications

Used in glass manufacturing, electronics, jewelry (as semi-precious stones), and as a common component in construction sand and gravel.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'Quarz', which likely originated from Slavic terms meaning 'hard'.

Field identification & locations

Identify by its hardness (scratches glass), lack of cleavage, and glassy appearance. Extremely common in river beds, beaches, and mountain trails worldwide.