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Cleavage (mineral) identification and geology

The tendency of a mineral to break along flat planes of weakness determined by the arrangement of atoms in its crystal structure. Cleavage planes correspond to directions of weakest bonding and are described by the number of directions, the angles between them, and the quality perfect, good, fair, poor . Cleavage is one of the most diagnostic physical properties for mineral identification. Field: mineralogy. Example: Calcite exhibits three directions of perfect rhombohedral cleavage at approximately 75° and 105°, producing characteristic rhombohedron-shaped fragments regardless of the original crystal shape.. Related terms: Fracture, Crystal structure, Parting, Hardness.

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  • Previous: Clast — An individual fragment or grain of rock or mineral produced by the mechanical weathering and erosion of a pre-existing rock.
  • Next: Cleavage (rock) — A type of secondary foliation in metamorphic rocks formed by the parallel alignment of platy minerals micas, chlorite or by the dissolution and removal…
  • Hardness

Sources, scope & corrections

These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.

Editorial owner
GeoMiner
Last updated
2026-03-30T15:19:41.970235+00:00
Review status
Published; not independently peer-reviewed
  • USGS Thesaurus — U.S. Geological Survey. Controlled earth-science terminology used to describe USGS information resources.
  • Glossary of Geologic Terms — U.S. National Park Service. Geologic definitions prepared by the NPS Geologic Resources Inventory.

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Common questions

What does Cleavage mineral mean in geology?
The tendency of a mineral to break along flat planes of weakness determined by the arrangement of atoms in its crystal structure. Cleavage planes correspond to directions of weakest bonding and are described by the number of directions, the angles between them, and the quality perfect, good, fair, poor . Cleavage is one of the most diagnostic physical properties for mineral identification.
What is an example of Cleavage mineral?
Calcite exhibits three directions of perfect rhombohedral cleavage at approximately 75° and 105°, producing characteristic rhombohedron-shaped fragments regardless of the original crystal shape.
Which earth-science field uses the term Cleavage mineral?
Cleavage mineral is used in mineralogy.
Which terms are related to Cleavage mineral?
Related terms in this reference are Fracture, Crystal structure, Parting, Hardness.

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