The formation of metamorphic rocks normally involves the change of other rocks through

Metamorphic rocks form when other rocks are changed by heat, pressure, and/or chemical reactions. The process of forming metamorphic rocks is called metamorphism. Heat and pressure can come from deep within the Earth or from the weight of overlying rocks. Chemical reactions can occur when fluids seep through rocks, dissolving and re-depositing minerals. This transformation can occur without melting the original rock, and can lead to the formation of new minerals and the rearrangement of existing ones, creating a new rock with unique characteristics. Tension and folding may play a role in the process of metamorphism, but they are not the primary agents of change.