ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001)
Mg 3(Al,Cr) 2(SiO 4) 3Gemdat.org , Management Team (2012)
Mg 2Al 4Si 5O 18Ulrich Henn and Claudio C.