Cleavage, to a mineralogist, means the tendency of some minerals to split or break along planes, and luster is a reflective property of mineral surfaces.
(Cleavage; means; the tendency of some minerals to split or break along planes) (luster; is; a reflective property of mineral surfaces)
Cleavage luster
means is
the tendency of some minerals to split or break along planes
a reflective property of mineral surfaces