Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
Subconchoidal, Uneven, Conchoidal, Uneven
KNa 2Li(Fe2+ ,Mn2+ ) 2Ti 2Si 8O 24Michael OâDonoghue , Gems, Sixth Edition (2006)
Mn2+ Al(PO 4)(OH) 2H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)