Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001)
Na 2(Ti,Fe)Si 4(O,F) 11Ulrich Henn and Claudio C.
CaTiSiO 5Ulrich Henn and Claudio C.