Diamond type
Diamond type is a method of scientifically classifying diamonds by the level and type of their chemical impurities. Diamonds are separated into four types: Type Ia, Type Ib, Type IIa, and Type IIb. The impurities measured are at the atomic level within the crystal lattice of carbon atoms and so, unlike inclusions, require an infrared spectrometer to detect.
Rough diamond
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).