Definition: Flakes of metal can peel off the surface of a coin after the strike. Such defects are generally attributed to the presence of contaminants in the alloy.  In some instances, flakes of metal lift off the face of a coin as the result of an inadequately mixed alloy.

A more dramatic and instructive example of a lamination flake that broke away after the strike can be seen in the above image of a 1944-D Lincoln cent.  The floor of the depression, which was left behind by the missing flake, is quite dark and probably represents the contaminants that caused the metal to separate in the first place.