metamorphic
Quartzite
Quartzite (SiO2)
Hardness: 7 Mohs, Color: tan to creamy white, Luster: vitreous to waxy (especially when polished), Crystal Structure: trigonal (microcrystalline), Cleavage: none, Specific Gravity: 2.6-2.7
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 Mohs, Color: tan to creamy white, Luster: vitreous to waxy (especially when polished), Crystal Structure: trigonal (microcrystalline), Cleavage: none, Specific Gravity: 2.6-2.7
Formation & geological history
Formed from the metamorphism of quartz sandstone under high heat and pressure, causing quartz grains to recrystallize and fuse together. Typically Precambrian to Paleozoic age depending on location.
Uses & applications
Used as a decorative stone, in construction as crushed stone for road gravel and railway ballast, and in the ceramic and glass industries. Polished specimens are popular for meditation and home decor.
Geological facts
Quartzite is so strong that when it breaks, it fractures through the quartz grains rather than along the boundaries between them, unlike sandstone.
Field identification & locations
Identified by its extreme hardness (cannot be scratched by a steel knife) and its grainy but fused texture. Often found in mountain ranges where tectonic plates have collided.
More like this
