FRACTURE
Fracture: mineral breaks along random, irregular surfaces.
Fracture surfaces: rough
and irregular and appear duller than cleavage planes.
Some minerals (e.g., quartz) break along
numerous small, smooth, curved surfaces = conchoidal
fractures.
Other types of fracture have descriptive names:
Fibrous: breaks into fibers.
Splintery: breaks into shards.
Hackly: the surface is studded with sharp and jagged elevations.
Even: The fracture-surface is flattish.
Uneven/Irregular:
The fracture-surface is rough by reason of minute
elevations and depressions - most minerals have an uneven/irregular fracture.