Granite is a natural compact kind of rock, which belongs to the category of igneous rocks, meaning the rocks that come from the hardening-crystallization of magma. The magma crystallization happens with changes in physico-chemical conditions, mostly pressure and temperature, which is accomplished by the rising of magma into higher horizons inside the lithosphere. Very often magma arrives until the earth's surface, which is a phenomenon that takes places in the mid- oceanic ridges and the continental volcanoes, and in this case it is called lava.

Igneous rocks appear in various forms, which depend from the morphology of the space, where the magma is and the conditions of the surrounding rocks or the rocks in which the magma intrudes, the depth of crystallization and the elements of which magma is consisted of.

The most important forms of igneous rocks are plutonic, volcanic and venous. Granites belong to the category of plutonic igneous rocks. Plutonic igneous rocks are the rocks that come from the crystallization of magma in deep horizons inside the lithosphere and are whole- crystalloid. They appear in large areas and have homogeneous mineral consistence.

Granites are rocks that are formed in the deep parts of the inside of the earth. In such depths the pressure and temperature conditions are quite high and for this reason the primal material from which granites come from is in liquid form. This liquid form is well known with the term 'magma'.

Magma gradually cools and hardens inside the earth, and is surrounded by the pre- existing rocks. From this gradual hardening granites are formed. Granites may stay millions of years in that primal depth of formation and at some point they may rise to the surface.
The components of a granitic rock and in addition its colour and properties, depend on the primal consistence of magma and in general this are: alkali- Feldspars, Quartz and Mica.

Granites, mostly and other plutonic rocks form large rock masses, which are the central cores of major mountain ranges, contributing likewise in the mountain- building process.

Many types of granite show evidence of being the result of metamorphic processes.