ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
(Ca,Cr)MgSi 2O 6Gemdat.org , Management Team (2012)
ZrSiO 4Michael OâDonoghue , Gems, Sixth Edition (2006)