Brittle, UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
ConchoidalAnthony et al, Handbook of mineralogy (2001), ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
(Mg,Fe)Al 3(BO 4)(SiO 4)OUlrich Henn and Claudio C.
SbTaO 4Ulrich Henn and Claudio C.