Describes the minerals cleavage. Cleavage is measured by quality and amount of sides that have cleavage. The first number describes the quality of cleavage (on a scale of 1-3 | 1=perfect; 2=good; 3=poor), and the second number describes the number of directions that exhibit cleavage. For example, a mineral with a cleavage of 1,2 has perfect cleavage in 2 directions. If the word "Indiscernible" is written in this field, than the cleavage is so poor it is not recognizable. If the word "None" is written in this field, then the mineral has no cleavage. If all sides have the same cleavage, than "All sides" is written.

If a mineral exhibits different cleavage on different sides of the mineral, than there will be two cleavage indicators separated by a semi-colon (;). For example, if the cleavage of a mineral is written 1,2 ; 3,1, then it has perfect cleavage in two directions, and poor cleavage on the other direction.

This field also describes the type of cleavage the mineral exhibits (if applicable), such as cubic, octahedral, rhombohedral, prismatic, and basal. The type of cleavage is separated by a - (dash), so for example a mineral with perfect basal cleavage would be written as 1,1 - basal.