Tags: Chemical Substance, Mineral.
Andalusite is an aluminium nesosilicate mineral with the chemical formula Al2SiO5. Andalusite is trimorphic with kyanite and sillimanite being the lower pressure mid temperature polymorph. At higher temp and pressure andalusite may convert to sillimanite. Thus as with its other polymorphs andalusite ia an aluminosilicate index mineral providing clues to depth and pressures involved in producing the host rock.
