Granite is a hard igneous rock having a coarse-grained surface, chiefly composed of four minerals viz., quartz, alkali feldspar, plagioclase feldspar, and hornblende. These minerals provide the different colors to the granite that it possesses. Granite being an igneous rock, is formed from the process of magma cooling.
This magma, which cools far below the earth's surface at a slow and steady rate, results in the expansion of the aforementioned minerals to a level that they can be conveniently seen with naked eyes. An important thing about granite is that it is not a homogeneous rock, thus its chemical properties vary according to its location.
The worldwide standard of the average proportion of different chemical components that are present in granite is given below:
| Silicon Dioxide (SiO2) | 70-77% |
| Aluminum oxide (Al2O3) | 11- 14% |
| Aluminum oxide (Al2O3) | 11- 14% |
| Potassium Oxide (K2O) | 3 - 5% |
| Soda(Na2O) | 3 - 5% |
| Calcium Oxide (CaO) | 1.82% |
| Iron(Fe2O3) | 1.22% |
| Iron(FeO) | 1.68% |
| Magnesia(Mg0) | 0.71% |
| Titanium Dioxide(TiO2) | Less than 1%(0.30%) |
| Manganosite (MnO) | 0.05% |
| Water(H2O) | 0.03% |
