Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Na 2(Ti,Fe)Si 4(O,F) 11Ulrich Henn and Claudio C.
LiAl(PO 4)(OH,F)Walter Schumann , Gemstones of the world (2001) More from other references