Many gemstones can be divided in one or more directions. Rupture occurs along perfectly flat planes. This attribute is called "sleavage" and depends on the lattice structure of the crystal. Depending on how easily a gem can be divided, one can distinguish between perfect, good and unclear splitting. A stone that cannot be divided at all has "no splitting". The splitting of a gemstone must be taken into account when cutting, polishing and setting the stone because a slight blow or excessively strong pressure can all often cause a gemstone to split.