A rough diamond is a diamond rock which has not been cut or processed. They come in a variety of naturally occurring shapes including octahedrons (eight sided bi-pyramid), cubic and triangular (most commonly macles). A raw diamond or rough diamond can also be a type of diamond which is not fully developed or can have less brilliance which should not it had. Extreme heat and pressure beneath the ground are said to make the carbon atoms to fuse at a specified structure.