A rock cycle diagram is an illustration of how metamorphic, sedimentary and igneous rocks relate to each other. The diagram also indicates a recurring sequence of the changes that occur in these rocks.
The rock cycle diagram indicates how rocks change from one type to another and back again as forces within the Earth push them either closer or further from the surface. When rocks move deep under the Earth's surface, they melt into magma, which solidifies into igneous rocks.
High temperatures transform these rocks transform into metamorphic rocks, which erode when exposed to the atmosphere to form tiny grains that fuse into sedimentary rocks. This transformation forms the rock cycle, as represented using a rock cycle diagram.