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.