Noun
A mineral of the feldspar family, commonly occurring in small glassy crystals, also a constituent of some igneous rocks. It is a lime feldspar. See Feldspar.
Source: Webster's dictionaryThere are several named plagioclase feldspars that fall between albite and anorthite in the series. Source: Internet
The following table shows their compositions in terms of constituent anorthite and albite percentages. Source: Internet