Micaceous, Brittle
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001)
KAl 2AlSi 3O 10(OH) 2Walter Schumann , Gemstones of the world (2001) More from other references
(Zn,Mn2+ ,Fe2+ )(Fe3+ ,Mn3+ ) 2O 4Anthony et al , Handbook of mineralogy (2001)