orthoclase

A white to yellowish red monoclinic mineral of the potassium feldspar group that forms from medium- to low-temperature magmas.

Common or potash feldspar, a silicate of aluminium and potassium, occurring in monoclinic crystals and also massive.

Common or potash feldspar crystallizing in the monoclinic system and having two cleavages at right angles to each other. See feldspar.

Potassium aluminum silicate, KAlSi3O8, a common feldspar of igneous, plutonic, and metamorphic rocks. Orthoclase is the main feldspar of pegmatite occurrences, where it is most commonly flesh-colored. Orthoclase is used in the ceramic and glass industries and as a decorative gravel.

a white or colored monoclinic feldspar