metamorphic
Quartzite
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: White to grey, sometimes reddish or pinkish due to iron impurities; Luster: Vitreous to waxy; Structure: Granoblastic (sugar-like) texture; Cleavage: None, breaks with a conchoidal or irregular fracture.
- Hardness
- 7 on Mohs scale
- 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: White to grey, sometimes reddish or pinkish due to iron impurities; Luster: Vitreous to waxy; Structure: Granoblastic (sugar-like) texture; Cleavage: None, breaks with a conchoidal or irregular fracture.
Formation & geological history
Quartzite is formed through the metamorphism (heat and pressure) of quartz-rich sandstone. Most quartzite is from the Proterozoic or Paleozoic eras. It typically forms at convergent plate boundaries.
Uses & applications
Used extensively in construction as crushed stone for road gravel and railway ballast. Due to its hardness, it is also used for floor tiles, wall coverings, and countertops. In some cases, high-purity quartzite is used to produce glass and silicon.
Geological facts
Quartzite is so tough that it can cut through steel. It is much more resistant to weathering than the sandstone it originated from, which is why it often forms the tops of ridges and hills.
Field identification & locations
Identify in the field by its ability to scratch glass and its grainy, 'sugary' texture on fresh surfaces. Unlike marble, it will not fizz with acid. It is commonly found in mountain ranges throughout the world, such as the Appalachians and the Alps.
More like this
