shining a light on the mineral. soaking the mineral in water. rubbing a penny against the mineral. breaking off a piece of the mineral.
A student has a mineral sample. He wonders if the sample is the mineral mica. He knows the cleavage pattern of mica is a smooth, flat sheet. The student can best find out the cleavage pattern of the sample by

Options:
- shining a light on the mineral.
- soaking the mineral in water.
- rubbing a penny against the mineral.
- breaking off a piece of the mineral.

breaking off a piece of the mineral.