Uneven, Splintery, Conchoidal, Uneven, Splintery, Conchoidal, UnevenWalter Schumann, Gemstones of the world (2001)
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
SiO 2Arthur Thomas , Gemstones (2009)
(Ca,Cr)MgSi 2O 6Gemdat.org , Management Team (2012)