Granite

Granite is a common and widely-occurring group of intrusive felsic igneous rocks that form at great depths and pressures under continents. Granite consists of orthoclase and plagioclase feldspars, quartz, hornblende, biotite, muscovite and minor accessory minerals such as magnetite, garnet, zircon and apatite. Rarely, a pyroxene is present. Ordinary granite always carries a small amount of plagioclase, but when this is absent the rock is referred to as alkali granite. An increasing proportion of plagioclase feldspar causes granite to pass into granodiorite. A rock consisting of equal proportions of orthoclase and plagioclase plus quartz may be considered a quartz monzonite. A granite containing both muscovite and biotite micas is called a binary granite. Depending upon the proportions of feldspar and quartz, the Mohs hardness of granite ranges between 5.5 and 7 http://www.findstone.com/daniel1.htm. The average density is 2.75 g/cm3 with a range of 1.74 to 2.80.

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The word granite comes from the Latin granum, a grain, in reference to the coarse-grained structure of such a crystalline rock.

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Intrusive: Redirect Intrusion...

Felsic: Felsic is a term used in geology to refer to silicate minerals, magmas, and rocks which are enriched in the lighter elements, such as silica, oxygen, aluminium, sodium, and potassium. The term combines the words "feldspar" and "silica."...

Igneous: REDIRECT Igneous rock...

Granite related Images and Photos (experimental)

Granite Boulders at Wineglass Bay	Granite Causeway St. Michael's Mount United Kingdom	Joshua Trees Granite Bolder Sunrise CA	Beauty of Granite Pass
The Head of a Forty-Four-Foot-Long Granite Statue of a Reclining Buddha Entering Nirvana	Upper Yosemite Falls Cascades Down the Sheer Granite Walls of Yosemite Valley	A Climber Negotiates the Second Pitch of Previously Unclimbed 3 600-Foot Granite Wall in Greenland