Rock - Research Article from World of Earth Science

This encyclopedia article consists of approximately 4 pages of information about Rock.
This section contains 1,004 words
(approx. 4 pages at 300 words per page)
Buy the Rock Encyclopedia Article

Rock

To the geologist, the term rock means a naturally occurring aggregate of minerals that may include some organic solids (e.g., fossils) and/or glass. Rocks are generally subdivided into three large classes: igneous, sedimentary, and metamorphic. These classes relate to common origin, or genesis. Igneous rocks form from cooling liquid rock or related volcanic eruptive processes. Sedimentary rocks form from compaction and cementation of sediments. Metamorphic rocks develop due to solid-state, chemical and physical changes in pre-existing rock because of elevated temperature, pressure, or chemically active fluids.

With igneous rocks, the aggregate of minerals comprising these rocks forms upon cooling and crystallization of liquid rock. As crystals form in the liquid rock, they become interconnected to one another like jigsaw puzzle pieces. After total crystallization of the liquid, a hard, dense igneous rock is the result. Also, some volcanic lavas, when extruded on the surface and cooled...

(read more)

This section contains 1,004 words
(approx. 4 pages at 300 words per page)
Buy the Rock Encyclopedia Article
Copyrights
World of Earth Science
Rock from World of Earth Science. ©2005-2006 Thomson Gale, a part of the Thomson Corporation. All rights reserved.
Follow Us on Facebook