Metamorphic rocks, like the name suggests, morphed from rocks that already existed. These rocks form through changes in conditions like heat and pressure. The type of metamorphic rock that forms depends on how much heat or pressure is involved. During the transformation, metamorphic rocks can change properties such as shape and texture. In ancient Greece, pillars, sculptures, and cities were built from marble, a type of metamorphic rock. Today, marble and other types of metamorphic rock are still used in construction.