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