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