Metamorphic rocks are produced from pre-existing rock that has been altered, but not yet melted by the pressure and heat from the deep surface of the Earth. The rocks originate from non-metamorphic rocks that have been changed due to pressure and temperature. The changes in pressure and temperature of the rocks cause the minerals to deform and re-crystallize. Most metamorphic rocks are formed from limestone and slate. If the pressure and heat increases enough to make a rock melt, magma will form and igneous rocks will also form. There are two categories of metamorphic rock: foliated and unfoliated. Foliated and unfoliated are characteristics of the rocks that describe the different textures. Foliation is the property a rock has if its minerals are banded. If the minerals are not banded,...