Gemstones of the world (2001), UnevenWalter Schumann, Gemstones of the world (2001)
ConchoidalAnthony et al, Handbook of mineralogy (2001), ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Not Available
Al 4(Ta,Nb) 3(O,OH,F) 14Ulrich Henn and Claudio C.