Granite has around 400 centigrade degrees temperature which is needed a long time like a few thousand years for temperature fall. Also, the temperature of granite is source of geothermal water. The movement of water floating unto ? through cracks of granites both raises the temperature of water by force of the high temperature of granite and also causes that soluble minerals get involved in constitution of the water. In this way geothermal water is formed.
Light colored and acidic combinational depth greywacke contains 10-40% quartz, 30-60% alkali feldspar and 35% micas and 10-35% dark colored minerals are called as granite. In commercial mean granite is used for too large greywacke group contains depth greywacke nearly in all combination. In market the term of granite is used as a common name for light colored rocks like gneiss, syenite, quartz monzonite, granodiorite, quartz diorite, diorite.
Granites are separated into groups according to characters of minerals. The size of grains are different for each granites. And also the colors are named according to feldspar. But, in the case that amount of quartz, hornblende and mica is over the color changes and it is named as white, light grey, dark grey, pink, red and olive green.
Specific gravity of a typical granite is 2.6 2.8 gr/cm, its real porosity 0.4-1.5 ½, its compression strength 1600 3300 kg/cm, its wearing resistance 5 8 kg/cm. Its hardness depends on minerals and it is accepted as 6.5.
Chemical composition and Occurrence
Granite contains more that 20% quartz by volume. It is not seen any kind of granite which contains more than 40% quartz among deep mass by volume. Graywackes being rich on account of harsh silicates and quartz belong to gabbro class. It is possible to see in form of feldspar pajioklas and orthoclase. The rate of one to another rate is less than two generally. It is arranged as muscovite, biotite, amphibole pyroxene or rarely fayalite. Generally one or two of these can be seen together. It cannot accepted as granite that stones contains more than 20% dark colored minerals by volume in addition that there is different dark colored minerals rate in variety classification.