What is an igneous or sedimentary rock that has been changed by extreme pressure or heat?

An igneous or sedimentary rock that has been changed by extreme pressure or heat is known as a metamorphic rock. This transformation processes, called metamorphism, alters the rock's mineral composition and texture without melting it. Common examples of metamorphic rocks include marble, which originates from limestone, and schist, which can form from shale. These changes often occur deep within the Earth's crust due to tectonic activity or heat from nearby magma.