UnevenArthur Thomas, Gemstones (2009) Tough, UnevenArthur Thomas, Gemstones (2009) Tough, Brittle, Uneven
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Uneven
Mn 8Si 6O 15(OH,Cl) 10Ulrich Henn and Claudio C.
Mn 3B 7O 13ClMichael OâDonoghue , Gems, Sixth Edition (2006)