Fracture

The separation of material into two or more parts. Fractures are often described by the appearance of the surface of the break in a piece of steel. Crystalline is bright and glittering, failure having developed along the cleavage planes of individual crystals and can be typical of brittle material. A silky fracture has a smooth dull grain indicative of ductile material such as a mild steel. In tensile testing fractures are described by shape, e.g. cup and cone.