metamorphic
Quartzite River Stone
Quartzite (primarily SiO2)
Hardness: 7 on Mohs scale; Color: Tan/Grey; Luster: Dull to Waxy; Structure: Granular/Crystalline; Cleavage: None; Specific Gravity: 2.6-2.7
- Hardness
- 7 on Mohs scale
- Color
- Tan/Grey
- Luster
- Dull to Waxy
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Physical properties
Hardness: 7 on Mohs scale; Color: Tan/Grey; Luster: Dull to Waxy; Structure: Granular/Crystalline; Cleavage: None; Specific Gravity: 2.6-2.7
Formation & geological history
Formed from the metamorphism of quartz-rich sandstone under intense heat and pressure, often found in riverbeds where it has been rounded by hydraulic action over thousands of years.
Uses & applications
Commonly used as decorative landscaping stone, construction aggregate, and in heavy industry for refractory materials due to high silica content.
Geological facts
Quartzite is so tough that it often survives long-term erosion better than the surrounding softer rocks, leading to the formation of ridges and river cobbles like this one.
Field identification & locations
Identify by its ability to scratch glass and its grainy, sugary appearance despite being a solid rock. Found in high-energy river environments and glacial deposits.
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