The forceful explosion of lava erupting from a volcano is the starting point for all igneous rocks. These rocks are made up of two or more solid, nonliving substances called minerals. Each igneous rock is identified by the kinds of minerals it contains, but they can also be grouped by their texture, their color, or how they formed. From molding granite into monuments to using pumice to trim your fingernails, igneous rocks are an important part of our world.