Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Uneven
(Zn,Mn2+ )OMichael OâDonoghue , Gems, Sixth Edition (2006)
Mn 3B 7O 13ClMichael OâDonoghue , Gems, Sixth Edition (2006)