These properties are established for most minerals. Thus if you have an unknown mineral, you perform a series of tests on that sample and compare them with the catalogued information on mineral properties. Cleavage Often, atoms for strong bonds in chains or sheets, and these sheets are connected by weaker bonds. Materials constructed in this way cleave in preferential directions. That is, you can break them more easily in certain directions.
Cleavage is thus a direct consequence of the geometry and the type of atomic bonds within a mineral.
Lighter color minerals are usually feldspar and quartz and are referred to as felsic. The true color of the mineral shows up when a sample is powdered. The streak is a way of checking the color of a mineral's powder. Luster is the shine of a mineral and reflects how light is reflected from the mineral. It can be metallic, pearly, glassy, or dull.