Here's why:
* Cleavage is the tendency of a mineral to break along smooth, flat planes of weakness. This is due to the arrangement of atoms within the mineral's crystal structure.
* Fracture describes the way a mineral breaks when it doesn't cleave.
Minerals that break with jagged surfaces can be further described with terms like:
* Conchoidal fracture: A curved, shell-like fracture (think of glass breaking).
* Hackly fracture: A jagged, uneven fracture, almost like a rough tooth.
* Splintery fracture: A long, thin, sharp fracture, like wood breaking.
* Irregular fracture: A fracture with no specific pattern.
So, when a mineral breaks with a jagged surface, it's said to have fracture, and the specific type of fracture helps further describe its properties.
