ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Uneven
Not Available
(Mn2+ ,Fe2+ ,Mg,Ca) 2(PO 4)(F,OH)Michael OâDonoghue , Gems, Sixth Edition (2006)
(K,Na) 2(Li,Fe) 3(Zr,Ti,Fe)Si 12O 30Ulrich Henn and Claudio C.