Fracture of polycrystalline materials by crack propagation through the grains.
A Transgranular fracture is a fracture that follows the edges of lattices in a granular material, ignoring the grains in the individual lattices. This results in a fairly smooth looking fracture with less sharp edges than one that follows the changing grains. Transgranular fractures are similar to wooden jigsaw puzzle pieces with the grains showing, but with each piece having grains running in a different direction. An intergranular fracture follows the edges of the puzzle pieces, ignoring the grains in the wood. This is opposed to an intergranular fracture.