This determines a mineral's many physical properties. Some minerals such as malachite are always one color, but minerals such as quartz exhibit many colors due to impurities in their chemical structure.
Cleavage refers to a smooth parting.
There are three directions of symmetry within a crystal. Some have no cleavage at all. Fracture describes an irregular break on the surface of a mineral that has no cleavage. There are many terms used to describe this, such as uneven, splintery, and conchoidal. Specimens harder than the plate will leave no streak.