Rocks are mixtures of one or more minerals. Just like the apples, butter, flour, and sugar are the ingredients of apple pie, minerals like quartz, mica, and feldspar are the ingredients of an igneous (from the Latin word for fire) rock called granite.
Igneous rocks come from melted rock material, or magma, that lies beneath Earth’s surface. Igneous rocks form when magma from inside the Earth moves toward the surface, or is forced above the Earth’s surface as lava and ash by a volcano. Here it cools and crystallizes into rock. There are two categories of igneous rocks. When magma crystallizes under Earth’s surface, it produces intrusive igneous rock with large crystals. When lava crystallizes above Earth’s surface, it produces extrusive igneous rock with crystals that are too small to see. Igneous rocks are very hard and made of interlocking crystals.