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Feldspar mineral, calcium aluminosilicate (CaAlSiO), that occurs as white or grayish, brittle, glassy crystals. Primarily a rock-forming mineral, it is used in the manufacture of glass and ceramics. Anorthite occurs in basic igneous rocks (seeacid and basic rocks).
This entry comes from Encyclopædia Britannica Concise. For the full entry on anorthite, visit Britannica.com.