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.
Table of Cleavage Types Used in this Database
Cleavage
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.
For Further Information on Cleavage
Search the Mineralogy Database
Example Subject Searches
Example:cleavage perfect finds all minerals with perfect
cleavage. Example:"cleavage-00*" finds all minerals a basal cleavage.