metamorphic
Quartzite
Metamorphosed Quartz Sandstone
Hardness of 7 on the Mohs scale, colors range from white to gray, yellow, and orange due to iron oxide impurities, vitreous to greasy luster, trigonal crystal system (microcrystalline or interlocking quartz grains), lacks distinct cleavage, specific gravity of 2.65.
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 of 7 on the Mohs scale, colors range from white to gray, yellow, and orange due to iron oxide impurities, vitreous to greasy luster, trigonal crystal system (microcrystalline or interlocking quartz grains), lacks distinct cleavage, specific gravity of 2.65.
Formation & geological history
Formed when quartz-rich sandstone is subjected to high heat and pressure, typically through tectonic compression during mountain-building events (orogeny).
Uses & applications
Used in construction, as crushed stone for roads, railway ballast, manufacturing of silica brick, and sometimes as a decorative dimension stone or in countertops.
Geological facts
Quartzite is extremely durable and resistant to chemical weathering, which is why ridges formed of quartzite often persist as prominent mountain crests or hills.
Field identification & locations
Can be identified by its sugary texture on fractured surfaces and its inability to be scratched by a steel knife. It does not fizz with hydrochloric acid.
More like this
