mineral
River Quartz Cobble
Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale; Color: Tan, white, and smoky brown; Luster: Vitreous to waxy (weathered); Crystal Structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- Tan, white, and smoky brown
- Luster
- Vitreous to waxy (weathered)
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Physical properties
Hardness: 7 on Mohs scale; Color: Tan, white, and smoky brown; Luster: Vitreous to waxy (weathered); Crystal Structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed through hydrothermal processes or igneous crystallization and later eroded and polished by water action in a river or stream environment over thousands of years.
Uses & applications
Primarily decorative in landscaping, used as an abrasive in industrial sandblasting, or as a source of silica for glass manufacturing.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. This specific specimen shows 'chatter marks' and rounding typical of fluvial transportation.
Field identification & locations
Identify by its ability to scratch glass and lack of reaction to acid. Commonly found in riverbeds, glacial tills, and beaches globally.
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