metamorphic
Quartzite
Metamorphic rock primarily composed of Quartz (SiO2)
Hardness: 7 on Mohs scale; Color: Reddish-brown to white/tan; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); High durability.
- Hardness
- 7 on Mohs scale
- Color
- Reddish-brown to white/tan
- Luster
- Vitreous to dull
Identified More metamorphic →
Explore Quartzite 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: Reddish-brown to white/tan; Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); High durability.
Formation & geological history
Formed through the regional metamorphism of quartz-rich sandstone. High temperatures and pressures cause the quartz grains to recrystallize and fuse together.
Uses & applications
Used as a decorative stone in landscaping, as a railway ballast, in road construction, and occasionally in jewelry (beads) or as a source of silica for glass manufacturing.
Geological facts
Quartzite is so tough that it often outlasts the surrounding rocks in erosion processes, often forming the caps of ridges and mountains. It will scratch glass easily.
Field identification & locations
Look for a granular, sugary texture on fresh surfaces that breaks across rather than around grains. Commonly found in mountain belts (Appalachians, Alps) and as water-worn pebbles in riverbeds or beaches.
More like this
