Uneven, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
ConchoidalAnthony et al, Handbook of mineralogy (2001), ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
(Mg,Fe) 5(SiO 4) 2(F,OH) 2Ulrich Henn and Claudio C.
CaBe 2(PO 4) 2Michael OâDonoghue , Gems, Sixth Edition (2006)