ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Ca 3Fe 2(SiO 4) 3Arthur Thomas , Gemstones (2009)
ZrSiO 4Michael OâDonoghue , Gems, Sixth Edition (2006)