Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
Subconchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Conchoidal
Na 2(Ti,Fe)Si 4(O,F) 11Ulrich Henn and Claudio C.
LiAlSi 4O 10Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references