Not Available
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Ca 2(Mg,Fe,Mn,Al) 2(SiO 4)(Si 2O 7)(OH) 2 · H 2OUlrich Henn and Claudio C.
Ca 2B 5SiO 9(OH) 5Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references