Anorthite is a naturally occurring mineral and an important member of the plagioclase feldspar series. Scientifically, it is classified as a calcium aluminum silicate with the chemical formula CaAl₂Si₂O₈. It represents the calcium-rich end of the plagioclase series, with albite being the sodium-rich counterpart. Anorthite crystallizes in the triclinic crystal system and is widely studied in geology due to its role in igneous and metamorphic rocks. This mineral is typically found in colors such as white, gray, or colorless, although it may occasionally show pale yellow or greenish tones due to impurities. It is usually opaque to translucent, but rare transparent crystals can be faceted for collectors. Anorthite has a vitreous (glass-like) luster, which gives it a subtle shine when polished.