metamorphic
Quartzite Pebble (River Rock)
Metamorphic Quartzite (SiO2)
Hardness: 7 on Mohs scale. Color: Tan, beige, light brown with iron oxide staining. Luster: Dull to vitreous, granular texture. Cleavage: None. Specific gravity: 2.65.
- Hardness
- 7 on Mohs scale
- Color
- Tan, beige, light brown with iron oxide staining
- Luster
- Dull to vitreous, granular texture
Identified More metamorphic →
Explore Quartzite Pebble (River Rock) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 on Mohs scale. Color: Tan, beige, light brown with iron oxide staining. Luster: Dull to vitreous, granular texture. Cleavage: None. Specific gravity: 2.65.
Formation & geological history
Formed from the regional or contact metamorphism of quartz sandstones. Subsequently weathered, eroded, and rounded by fluvial or coastal water action into a smooth beach/river pebble.
Uses & applications
Commonly used in landscaping, river rock aggregate, aquarium decoration, and construction. Smooth specimens are often collected by hobbyists or used for rock painting.
Geological facts
Quartzite is so hard and resistant to chemical weathering that it often forms the tops of ridges and hills. When hit with a hammer, quartzite breaks across its grain rather than around individual sand grains like sandstone.
Field identification & locations
Identified by its rounded pebble shape, sandy/granular texture under magnification, extreme hardness (scratches glass easily), and dull earthy luster with rusty iron staining. Extremely widespread in riverbeds, glacial tills, and beaches worldwide.
More like this
