conchoidal or uneven
Fracture
conchoidal to uneven
Copper fractures.
An opal has no cleavage. It does, however, have a fracture. It's fracture is Conchodial to uneven.
Fracture.
Fracture
Fracture
It has both: uneven fracture, and perfect cleavage in three directions.
UnevenWhen it is shattered, the pieces are uneven
Fracture.
The answer is fracture