Fleshed red, white or gray.

Potassium feldspar, also known as orthoclase, is an aluminosilicate mineral of alkali metals or alkaline earth metals such as potassium, sodium, and calcium, and belongs to the feldspar group minerals. It usually appears fleshy red, white or gray, and is a mineral of the monoclinic crystal system. The crystals are in the form of short columns or thick plates. Twin crystals are common, and some are in the form of granular or massive aggregates.