ConchoidalAnthony et al, Handbook of mineralogy (2001), ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
Al 4(Ta,Nb) 3(O,OH,F) 14Ulrich Henn and Claudio C.
Al 2SiO 5Arthur Thomas , Gemstones (2009)