Unlike dislocation glide, movement of a twin boundary significantly and permanently alters the orientation of the crystal. The orientation of the twin plane, and the misorientation across the twin boundary will be precisely the same for any particular type of twin, and the process of twinning is essentially instantaneous, there is not a gradual change in crystallographic orientation, as the twin boundary moves across a region, the crystal lattice flips, and a discrete increment of deformation is attained. Further deformation of the grain may cause more material to become twinned, but it does not further deform the twinned volume (at least not by the same type set, other twins, or other mechanisms may of course be activated). Deformation twins can often be distinguished from growth twins (that form during crystal growth) by being thinner, and having wedge shaped terminations. They are particularly important in the low temperature deformation of calcite, and the deformation of plagioclase.