ConchoidalAnthony et al, Handbook of mineralogy (2001), ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001)
Al 4(Ta,Nb) 3(O,OH,F) 14Ulrich Henn and Claudio C.
Be3Al2SiO6