Twinning is common in all feldspars and follow certain twin laws such as the Albite Law, the Pericline Law, the Carlsbad Law, the Manebach Law and the Baveno Law. In orthoclase, only the Carlsbad Law, the Manebach Law and the Baveno Law are seen. The Carlsbad Law twin produces what appears to be two intergrown crystals growing in opposite directions. Two different twin laws, the Manebach and Baveno laws, produce crystals with one prominant mirror plane and penetrant angles or notches into the crystal. Although twinning in general is common for orthoclase, single crystals showing a perfect twin are rare and are often collected by twin fanciers.
Color is off-white, yellow, or shades of red, orange to brown.
Luster is vitreous to dull if weathered. Transparency crystals are usually opaque, may be translucent or rarely transparent. Crystals have a nearly rectangular or square cross-section with slightly slanted dome and pinacoid terminations. Twinning is common. Cleavage is good in 2 directions forming nearly right angled prisms.