metamorphic
Quartzite
Metamorphic Rock (Mainly SiO2)
Hardness: 7 on Mohs scale; Color: Grayish-white to light green; Luster: Vitreous to dull; Crystal structure: Non-foliated/Granular; Cleavage: None (breaks with conchoidal fracture); Specific gravity: 2.6-2.7
- Hardness
- 7 on Mohs scale
- Color
- Grayish-white to light green
- Luster
- Vitreous to dull
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: Grayish-white to light green; Luster: Vitreous to dull; Crystal structure: Non-foliated/Granular; Cleavage: None (breaks with conchoidal fracture); Specific gravity: 2.6-2.7
Formation & geological history
Formed through the metamorphism of pure quartz sandstone under intense heat and pressure, typically during mountain-building events (orogeny). The individual quartz grains recrystallize into a locked mosaic.
Uses & applications
Used primarily in construction for decorative stone, glass manufacturing (if high purity), railway ballast, and occasionally in jewelry as a substitute for more expensive gems when dyed.
Geological facts
Quartzite is so tough that it often outlasts the surrounding rocks; in many mountain ranges, the highest peaks are made of quartzite because it is extremely resistant to chemical and physical weathering.
Field identification & locations
Identify in the field by its extreme hardness (it will easily scratch glass and steel) and its crystalline appearance. Look for it in folded mountain belts and ancient shield areas. Unlike marble, it will not fizz with acid.
More like this
