ConchoidalAnthony et al, Handbook of mineralogy (2001), ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
Uneven, UnevenArthur Thomas, Gemstones (2009)
Al 4(Ta,Nb) 3(O,OH,F) 14Ulrich Henn and Claudio C.
Cu 5(SiO 3) 4(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references