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Pictures of Igneous Rock Types


Granite consists of quartz (gray), plagioclase feldspar (white) and alkali feldspar (beige) plus dark minerals, in this case biotite and hornblende. (more below)
Type rock of continents
Photo (c) 2004 Andrew Alden, licensed to About.com (fair use policy)
"Granite" is used by the public as a catch-all name for any light-colored, coarse-grained igneous rock. The geologist examines these in the field and calls them granitoids pending laboratory tests. The key to true granite is that it contains sizable amounts of quartz and both kinds of feldspar. This article goes much deeper into granite.

This granite specimen comes from the Salinian block of central California, a chunk of ancient crust carried up from southern California along the San Andreas fault. Pictures of other granite specimens appear in the granite picture gallery. Also see the granite landforms of Joshua Tree National Park. And big closeup pictures of granite are available in the closeup rock wallpaper photos.

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