Igneous rocks that are mainly composed quartz and potassium feldspar have something called granitic composition or granitic rocks. There are two types of granitic rocks one is intrusive which means course-grained and the other one is extrusive which means fine-grained. Geologists also commonly refer to granitic rocks as felsic rocks, a term derived from the words feldspar and silica. Granitic rocks also have about 10 percent dark silicate materials and 70 percent silica. Granitic rocks are also a major contributor to the earths crust. There are two types of granitic rocks of granitic rocks one in intrusive that means it is course-grained. The other type is extrusive which means fine-grained. A common granitic rock is granite. It is course-grained and forms in cooling magma chambers. When mountains started forming the chambers full of granite got uplifted to the surface and started to form several mountains such as Enchanted Rock National Park, its mountains are made almost entirely out of granite. Granite is also one of the best-known examples of granitic rock. Another example of granitic rocks is rhyolite it is the extrusive equivalent of granite it is fine-grained and like granite it is made mostly of light colored silicates.