A positioning element for a counter die for making graphic marks on flat sheets for packaging is shown. It includes at least a ring 0.2 to 0.8 mm thick, shaped on both sides, and made of ferromagnetic material. The ring has a hole that fits into a mold cavity of the counter die. A mold for making a counter die containing a positioning element for a counter die for making graphic marks on flat sheets for packaging is also described. The mold is provided with sockets for fixing the position of rings, wherein each socket is a cylinder facing with its apex, a surface of the mold together with a milled base to a minimum depth equal to a thickness of the rings, a number of sockets being equal to number of rings.