The twins are formed because of a change in the normal growth mechanism. The effect of twinning on the lattice structure. Twin bands Figure 6. Twin bands in zinc. Atoms move a whole number of atomic spacing.
Atoms move fractional atomic spacing.
No change in lattice orientation. The steps are only visible on the surface of the crystal and can be removed by polishing. After polishing there is no evidence of slip. Lattice orientation changes. Surface polishing will not destroy the evidence of twinning.