The same mineral found in different parts of the world will always look the same and will have a characteristic crystal form and a consistent chemical formula. Minerals can be identified in rocks by a process of elimination. A variety of features can be used to identify specific minerals. Some of the most common are listed below. Minerals form crystals with specific shapes when they have been able to grow without obstruction.
Common shapes are prisms, pyramids, needles, cubes, and sheets .
Cleavage Minerals break along specific planes of weakness related to their atomic structure. Quartz has no cleavage planes but fractures irregularly. Moh's hardness scale Minerals are ranked from 1 to 10 based upon their relative hardness. Harder minerals can scratch softer minerals. Ten index minerals make up Moh's scale and other minerals are ranked relative to these.