Diamond crystal shapes can vary from the well-structured crystals to partially-grown, irregular shapes to fragments. When crystals grow together in clusters they are called polycrystalline agglomerates.
A definite relationship exists between the shape and performance of the diamond crystal. A high proportion of irregularly shaped, angular crystals are desirable for less severe applications ( see Fig. 1). As the shape of the crystals becomes blockier, the diamond product becomes more suited for applications of greater severity.
Experience has shown the optimum diamond product for applications with severe crystal loads is one that contains predominantly block-shaped crystals. This shape offers the greatest resistance to fracturing with a maximum number of points or edges and a minimum surface contact. The result is lower machine power requirements and longer tool life. The ideal diamond shape for sawing and drilling applications is a shape called "cubo-octahedron."