Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Brittle
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Fe 2SiO 4Michael OâDonoghue , Gems, Sixth Edition (2006)
MgAlBO 4Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references