Thursday, 19 March 2015

Granite

Granite

Granite is an intrusive igneous coarse grained rock. Granite is formed from the very slow cooling of the magma which provided sufficient time for the crystal to grow, large enough to be seen with an unaided eye. Granite consists of mainly quartz and feldspar with minor amount of mica, amphibole and other minerals. This mineral composition results in granite colours of red, pink, white and grey with dark minerals visible.
Granite is the most common igneous rock occurring on the Earth's surface so is readily distinguishable of the other igneous rocks. Granite is also used in different forms which can be seen in a daily life things.

Granite word usage

Granite in a geology course is used for igneous rock that is light in colour and composed mainly of feldspar and quartz.
In petrography it is used for a rock in which quartz is 10 to 50 percent of felsic component and alkali feldspar account for 65 to 90 percent of total feldspar content.

Granite in Earth's crust

Granite is abundant in the Earth's crust found at many mountain ranges in their cores known as batholiths. The granite grains are larger which hence proved that it has been grown of magma slow cooling in a long period of time. These are exposed at the surface by the uplifting process as they grow deeper in the crust, no other way would have been present at surface. 
Granite when not exposed on the surface and is covered by sedimentary rocks doesn't mean they aren't there. They are present beneath the sedimentary cover as deeper crust have magma chambers which rise from mantle. So these hard rocks makes the basement rocks of the crust, hard enough to endure the sedimentary rocks overburden.

Uses of granite

Granite is used as a dimension stone, its properties of hard rock makes it well suitable for the job. These are resistive to abrasion, strong enough to endure the weight,inert to the weathering and it can be polished. 

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