Answer is: cleavage and luster are examples of qualitative observations.
Qualitative observationare information about the quality of substances.
In qualitative observation, informations are collected using senses (sight, hearing, taste, smell and touch).
Qualitative observations are not measurable and cannot be recorded in terms of numbers.
Luster is the way light interacts with the surface of a mineral.
Cleavage is the tendency of mineral to split along definite crystallographic structural planes.
