ConchoidalAnthony et al, Handbook of mineralogy (2001), ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Uneven, Uneven, Gems, Sixth Edition (2006)
None
2,1 basal ; 2,1 prismatic ; 3,1 pinacoidal
Al 4(Ta,Nb) 3(O,OH,F) 14Ulrich Henn and Claudio C.
KAlSi3O8