Granitoid is a term used to describe a family of coarse-grained igneous rocks that are primarily composed of quartz, feldspar, and mica. These rocks are typically light in color and form from the slow crystallization of magma beneath the Earth's surface. Granitoids are commonly found in continental crust and are significant in geology for understanding the processes of crust formation. The most well-known type of granitoid is granite, which is widely used in construction and as a decorative stone. Other related types include granodiorite and tonalite, which have varying proportions of the main minerals. Granitoids play a crucial role in the rock cycle and are important for studying Earth's geological history.