metamorphic rock

Metamorphic rocks are formed when existing rocks, called parent rocks, are transformed by heat, pressure, or chemically active fluids deep beneath Earth's surface. These conditions cause the original minerals to change into new minerals, or realign to produce different textures, without melting the rock completely. This process, known as metamorphism, results in rocks with distinctive features such as foliation (layered appearance) seen in slate or banding in gneiss. Metamorphic rocks are important in understanding Earth's interior and often serve as valuable materials in construction and art. Examples include slate, gneiss, and marble.