Granite is a common type of intrusive, felsic, igneous rock which is granular and phaneritic in texture.
A worldwide average of the chemical composition of granite, by weight percent:
It is not easy to measure the hardness of Granite. Granite is a rock composed of multiple minerals, typical Quartz, Feldspar, Biotite and Hornblende. Each of the minerals has a unique hardness. In other words, we can measure the hardness of individual material but not easy of granite as a rock.