Cleavage Meaning Geology. A pervasive parallel foliation of fine-grained platy minerals mainly chlorite and sericite in a direction perpendicular to the direction of maximum finite shortening developed in slate or other homogeneous sedimentary rocck by deformation and low-grade metamorphism. Schistosity a term used to describe repetitive and pronounced foliation of the type that is present in schists.
Although cleavage surfaces are seldom as flat as crystal faces the angles between them are highly characteristic and valuable in identifying a crystalline material. Cleavage is the tendency of a mineral to break along smooth planes parallel to zones of weak bonding. There are parallel cracks in this rock called cleavage.
Mineral Cleavage Test Video.
Cleavage is the ability of a mineral to break along preferred planes. As a tectonic foliation cleavage occurs as a response to tectonic activity. Cleavage is the result of weaker bond strengths or greater lattice spacing across the plane in question than in other directions within the crystal. Cleavage that is in the hinge of a fold parallel to the hinge surface of the fold and whose intersection lineation with bedding is parallel to the fold hinge.
