Conchoidal, Splintery, Fibrous, UnevenArthur Thomas, Gemstones (2009)
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
CaSO 4 -2(H 2O)Arthur Thomas , Gemstones (2009)
ZrSiO 4Michael OâDonoghue , Gems, Sixth Edition (2006)