Mineral Identification Key Cleavage. Cleavage refers to the way some minerals break along certain lines of weakness in their structure. Mica is a good example – breaking along very closely spaced flat planes that yield thin "sheets."
So, what is cleavage of a mineral?
Cleavage is the tendency of a mineral to break along smooth planes parallel to zones of weak bonding. Fracture is the tendency of a mineral to break along curved surfaces without a definite shape. These minerals do not have planes of weakness and break irregularly.
Why does cleavage occur in minerals?
Cleavage occurs in minerals that have specific planes of weakness. These planes or directions are inherent in the structure of the mineral and form from a variety of factors.
What is the cleavage of a rock?
Cleavage, in structural geology and petrology, describes a type of planar rock feature that develops as a result of deformation and metamorphism. The degree of deformation and metamorphism along with rock type determines the kind of cleavage feature that develops.