A common rock-forming potassium feldspar ranging in color from white to red.
A variety of feldspar, composed of potassium aluminum silicate, characterized by a monoclinic crystalline structure and found in igneous or granitic rock. Also called potash feldspar.
Orthoclase (Potasium Aluminum Silicate or alkali feldspar or K-spar, KAlSi3O8) is named for its angles of cleavage. In Greek, orthos means "right" and kalo means "to cleave"; its two cleavages are at right angles to each other. Orthoclase is a common monoclinic crystal found worldwide, often in granite and other igneous rocks. It is also called adularia (moonstone, an oplescent variety) and orthose. This vitreous feldspar is colorless to white to pink to greenish, and is transluent to transparent. Orthoclase has a hardness of 6 and a specific gravity of 2.53-2.56. The streak is white. Orthoclase is used an an abrasive in scouring powder. When orthoclase is mixed with kaolin and quartz, the result is porcelain. You can use orthoclase to make your dishes and then wash them.
Orthoclase (KAlSi3O8) is an important tectosilicate mineral, which forms igneous rock. It is also known as alkali feldspar and is common in granite and related rocks.