Metamorphic rocks are transformed pre-historic rocks deep down in the crust of the Earth. They were formed as a result of high temperature and high pressure which brought about physical and chemical changes to their properties. These processes are that bring about great change are tectonic collisions, pressure from the weight of rock layers and hot molten lave from inside the Earth. Examples of these metamorphic rocks are the slate, marble and gneiss. One resource of this rocks is in the coastline of Brazil and also in mountainous regions.