quartzite

quartzite, usually metamorphic rock composed of firmly cemented quartz grains. Most often it is white, light gray, yellowish, or light brown, but is sometimes colored blue, green, purple, or black by included minerals. It results from the metamorphism of pure quartz sandstone. It is most easily distinguished from sandstone by the fact that it fractures across its constituent grains of sand, while sandstone fractures along the line of the cementing material between the grains of sand. Although most quartzites are metamorphic, some are sedimentary in origin, resulting from cementation of quartz sandstone by groundwater solutions containing pure quartz.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

More on quartzite from Fact Monster:

  • rock: Metamorphic Rocks - Metamorphic Rocks Metamorphic rocks originate from the alteration of the texture and mineral ...
  • Aravalli Hills - Aravalli Hills Aravalli Hills , hill system, N India, stretching 350 mi (560 km) through Rajasthan ...
  • sandstone - sandstone sandstone, sedimentary rock formed by the cementing together of grains of sand. The usual ...
  • sand - sand sand, rock material occurring in the form of loose, rounded or angular grains, varying in size ...
  • Devonian period - Devonian period Devonian period , fourth period of the Paleozoic era of geologic time between 408 ...

See more Encyclopedia articles on: Geology and Oceanography