metamorphic
Quartzite (River Pebble)
Recrystallized Quartz (SiO2)
Hardness: 7 on Mohs scale; Color: Tan, beige, or yellowish-white; Luster: Vitreous to waxy; Texture: Granular and smooth due to water erosion; Cleavage: None/Conchoidal fracture.
- Hardness
- 7 on Mohs scale
- Color
- Tan, beige, or yellowish-white
- Luster
- Vitreous to waxy
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 on Mohs scale; Color: Tan, beige, or yellowish-white; Luster: Vitreous to waxy; Texture: Granular and smooth due to water erosion; Cleavage: None/Conchoidal fracture.
Formation & geological history
Formed from the metamorphism of quartz sandstone under intense heat and pressure. This specific specimen has been further shaped and polished by the mechanical action of river water or glacial movement.
Uses & applications
Used extensively in construction as crushed stone, road ballast, and decorative landscaping rock. High-purity quartzite is used to produce glass and industrial silicon.
Geological facts
Quartzite is so hard it can scratch steel and glass. In its parent form (sandstone), it is porous, but the metamorphic process fuses the grains together into a dense, non-porous rock.
Field identification & locations
Identify in the field by its hardness (cannot be scratched by a knife) and its grainy, crystalline appearance. It is commonly found in riverbeds, glacial tills, and mountainous regions like the Appalachians or Alps.
More like this
