Orthoclase
An alkali feldspar that occurs in a variety of colors including yellow or shades of red. Gem quality orthoclase is most often colorless or a very pale yellow to greenish-yellow.
Orthoclase is named from the Greek "orthos" (right) and "kalo" (I cleave), referring to the fact that it cleaves at right angles. Transparent, gem quality crystals suitable for cutting or carving have been historically uncommon, but current mining of gemmy yellow othoclase crystals in Madagascar appears to be stable and productive. Orthoclase is not usually enhanced and is a moderately durable gem best worn in pendants, earrings and pins.
