End-member (Mg,Fe)2(Mg,Fe)5[Si4O11]2(OH,F)2, along with gedrite, of the calcium-poor, orthorhombic amphiboles. In anthophyllite Mg > Fe, whereas in gedrite Mg < Fe. It is found exclusively in metamorphic rocks, where it may occur with cordierite. Amosite is the asbestiform variety of anthophyllite.