Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Brittle
Na 2(Ti,Fe)Si 4(O,F) 11Ulrich Henn and Claudio C.
Mg 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006)