Intrusive igneous rocks are formed from magma that cools and solidifies beneath the Earth's surface. This slow cooling process allows large crystals to develop, giving these rocks a coarse-grained texture. Common examples include granite and diorite. These rocks are typically found in plutons, which are large bodies of intrusive rock. Because they form underground, intrusive igneous rocks are often exposed at the surface through erosion over time. Their formation is a key part of the rock cycle, contributing to the diversity of Earth's geology.