ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001)
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
CaTiSiO 5Ulrich Henn and Claudio C.
ZrSiO 4Michael OâDonoghue , Gems, Sixth Edition (2006)