Description: This is the Orthoclase specimen, from Pakistan, wide around 6.5cm. Orthoclase as one member of the Feldspar group, its Mohs Hardness is 6, contain K, Al, Si, O elements, Crystal system is Monoclinic. This Orthoclase specimen has bright luster, outstanding crystal, obvious geometric shape, transparent to translucent, biggest crystal center area is transparent, very interesting! From F. Lietard collection, 1997-year.