Any member of the series of abundant feldspar minerals that usually occur as light-to medium-grey-coloured, transparent to translucent grains or crystals. Plagioclase ranges in composition from albite to anorthite. It is used in the manufacture of glass and ceramics; iridescent varieties are valued as gemstones. The primary importance of plagioclase, however, derives from its role as a rock-forming mineral
A member of the feldspar mineral family Plagioclase feldspars are silicates that contain considerable sodium and calcium Feldspar crystals are stubby prisms, generally white to gray and a glassy luster
A group of feldspar minerals that form a solid solution series from albite (sodium aluminum silicate) to anorthite (calcium aluminum silicate). The plagioclase feldspars are found in igneous, plutonic, and metamorphic rocks. They all have the triclinic-pinacoidal crystal habit, but only Albite commonly occurs in well crystallized specimens