ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
(Ca,Cr)MgSi 2O 6Gemdat.org , Management Team (2012)
ZrO 2Arthur Thomas , Gemstones (2009)