ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
ZrO 2Arthur Thomas , Gemstones (2009)
(Ca,Mg,Mn)SiO 3Gemdat.org , Management Team (2012)