What combines to make rocks?

Rocks are formed from the combination of minerals, which are naturally occurring inorganic solids with a definite chemical composition and crystalline structure. They can also include organic materials and mineraloids. The processes that create rocks include cooling and solidification of magma (igneous rocks), compression and cementation of sediments (sedimentary rocks), and alteration under heat and pressure (metamorphic rocks). The specific combination and arrangement of these components determine the type of rock formed.