A usually white, hard mineral, Al2 SiO5 , occurring in highly metamorphosed rock as long, slender, fibrous crystals.
A very hard, mineral, aluminum silicate, Al2SiO5, usually found in metamorphic rock as long, slender crystals of various colors.
A usually white, pale-green or brown orthorhombic mineral occurring as long, slender, fibrous crystals in metamorphic rocks. It is a polymorph of andalusite and kyanite, but can form at higher temperatures than either of these. Chemical formula: Al2SiO5.