Cleavage: If a mineral is strained beyond its elastic limits, it will break. If it breaks irregularly then it shows fracture, if it breaks along regular surfaces related to the crystal structure then it shows cleavage. This cleavage depends on weaknesses in the crystalline make-up of the mineral and is a diagnostic property which can reveal additional information about the mineral. Cleavage Type               Cleavage Description Unknown                              Mineral too small to observe cleavage None                                     No cleavage Very Good                            Very good cleavage

                                   Perfect                                   Very good, shiny cleavage surface

                                   Imperfect                               Not perfect, equivalent to fair or good

                                   Good                                     Good, distinct cleavage surface

                                   Distinct                                  Distinct, recognizable cleavage surface

                                   Indistinct                                Poorly formed cleavage surface

                                   Fair                                        Fair, recognizable cleavage surface

                                   Poor                                       Poorly formed cleavage surface

                                   Parting                                   Developed only in some specimens