Conchoidal, Uneven, Conchoidal, Brittle, ConchoidalArthur Thomas, Gemstones (2009)
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Ca 3Fe 2(SiO 4) 3Arthur Thomas , Gemstones (2009)
MgAlBO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references