Flexi Says: Intrusive igneous rocks cool underground. Deep in the crust, the magma cools slowly. Slow cooling gives crystals a chance to grow. Intrusive igneous rocks have relatively large crystals that are easy to see. Intrusive igneous rocks are also called plutonic. A pluton is an igneous rock body that forms within the crust. Granite is the most common intrusive igneous rock that consists of minerals such as quart, feldspar, and mica. Intrusive igneous rocks are used in building, statues, decorations, jewelry, etc.
