Fibrous, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001)
AlAl6O3BSi3O18
(Zn,Mn2+ ,Fe2+ )(Fe3+ ,Mn3+ ) 2O 4Anthony et al , Handbook of mineralogy (2001)