It is the most common
intrusive rock on the Earth.
It is an intrusive
which means it is formed under the Earth's surface, in plutons and
other igneous intrusions, when magma cools.
Because magma cools relatively slowly there, granite is not the finest
grained, its grains are medium
It has an interlocking
texture, i. e. its grains are intelocked like in a puzzle.
It is always closely associated with mountain building and it is often
seen in large batholiths,
which have been uplifted and uncovered by erosion.
We see granite everywhere, and its texture is so typical it seems
really easy to identify.
But when we talk about granite, we mean what geologists actually call granitoids - a group
of granite-related rocks.
The actual granite needs laboratory methods to be idenitified.
El Capitan in Yosemity by Rick van der Meiden via Flickr.com
The different types of
granite include, but are not limited to white, pink,
porphyritic, hornblende, orbicular and rapakivi granite, porphyritic,
white and pink microgranite, tonalite, granodiorite and more.
Devils Marbles in Australia by Peter
Nijenhuis via Flickr.com
It is a felsic
rock, which contains about 70% silica.
Granite's main minerals are quartz,
however with so many different variations, the whole mineral
composition of course varies.
If the magma with the same composition forms an extrusive igneous rock,
it will be rhyolite.
Mount Rushmore in the northern US by Liz Lawley
Granite is widely used in buildings, kitchen countertops and
tombstones. Some of the famous occurences are Devils Marbles in
Australia, and El Capitan in Yosemity and Mount Rushmore in the