metamorphic
Quartzite
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: typically white to grey, but often yellow, tan, or orange due to iron oxide staining; Luster: Vitreous to dull; Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7.
- Hardness
- 7 on Mohs scale
- 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: typically white to grey, but often yellow, tan, or orange due to iron oxide staining; Luster: Vitreous to dull; Crystal structure: Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.7.
Formation & geological history
Formed through the regional metamorphism of quartz-rich sandstone. Under intense heat and pressure, the sand grains recrystallize and fuse together. It can be found in mountain ranges and eroded cratons globally.
Uses & applications
Used as crushed stone for road construction and railway ballast; as a decorative stone in architecture and landscaping; and in the manufacturing of glass and ceramics due to its high silica content.
Geological facts
Quartzite is so hard and chemically resistant that it often forms the ridges and peaks of mountain ranges because it resists erosion much better than surrounding rocks like marble or shale.
Field identification & locations
Identify in the field by its extreme hardness (cannot be scratched by a steel nail) and its grainy, crystalline texture that breaks through the grains rather than around them. It is commonly found in metamorphic terranes.
More like this
