Plutonic rocks, also known as intrusive igneous rocks, form beneath the Earth's surface when molten magma cools and solidifies slowly. This slow cooling process allows large crystals to develop, giving these rocks a coarse-grained texture. Common examples of plutonic rocks include granite and gabbro. These rocks are typically found in mountain ranges and batholiths, which are large masses of rock formed from cooled magma. Plutonic rocks are important for understanding the Earth's geology, as they provide insights into the processes that shape the planet's crust over millions of years.