what colour is feldspar
K-feldspar and plagioclase feldspar Feldspars have two cleavage planes that intersect at 90Â°. Fragments of pure feldspar crystals thus tend to form rectangular blocks with irregular ends. Feldspars have vitreous lusters and occur in opaque shades of white to gray to pink to very dark gray.Other rarer colors are also possible! The feldspars are divided into two main groups: Potassium feldspar (K-spar) and plagioclase (plag).-feldspar and plagioclase feldspar Feldspars have two cleavage planes that intersect at 90Â°. Fragments of pure feldspar crystals thus tend to form rectangular blocks with irregular ends. Feldspars have vitreous lusters and occur in opaque shades of white to gray to pink to very dark gray.