cleavage (mineralogy: tendency of a crystal)

cleave

to be broken, to break itself / to be divided; to crack; to be split / to be able to be divided; to be divisible / (colloquial) to be revealed; to be identified

something that is set one way and will not change; something that is fixed; something that is regular

fixed, settled, certain

along

good, fine, satisfactory, excellent

a satisfactory condition

to run along (a river, railway, road, etc.), to line (the shore etc.) / to follow (rules, guidelines, etc.)

minerals