Cleavage (crystal)
As cleavage the tendency is referred to in minerals and crystals to break at certain parallel planes in the crystal lattice. The cleavage is thus a particular type of fracture. Primarily as a technical- artisanal term is the word when you use rocks.
A Spaltbarkeitsebene minerals is a smooth surface that reflects light well. Spaltbarkeiten may vary well trained in different minerals differ in the resulting Spaltbarkeitsflächen / levels and the quality of their education. It is used not only for the classification of minerals, but leaves on the angles of the cleavage planes also provide insights into the crystal lattice.