Which type of rock is created by intense heat AND pressure?

The story behind the answer

Metamorphic rocks form when preexisting rocks are transformed by intense heat and pressure without melting. Minerals recrystallize, new minerals grow, and textures align, producing rocks like marble (from limestone), slate (from shale), and gneiss (from granite).

By contrast, igneous rocks crystallize from cooled magma or lava, and sedimentary rocks form from compacted and cemented sediments at relatively low temperatures and pressures. Diamond is a mineral, not a rock, formed deep in the mantle. Memory tip: “meta” = change, “morph” = form—rocks change form under mountain-building pressures.