Define cleavage and cleavage plane

Question

Define cleavage and cleavage plane

Answer 1

Cleavage (as used in chemistry) is the tendency of a crystalline solid to split or cleave along predictable and definite planes within the structure of the crystal.  The reason the cleavage takes places along these defined planes has to do with the way the atoms are arranged within the crystalline structure, and there are smooth and repeating areas that are vulnerable to splitting/cleavage.