Metamorphic rocks have been subjected to tremendous heat and/or pressure, causing them to change into another type of rock.
They are usually resistant to weathering and erosion and are therefore very hard-wearing.
Examples of metamorphic rocks include marble, which originates from limestone and slate, which originates from clay.
Slate and marble
Marble Caves of Lake General Carrera, Chile
Llanberis Slate Quarry, Wales