ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001)
Ca 3Fe 2(SiO 4) 3Arthur Thomas , Gemstones (2009)
Al 2Be 3Si 6O 18Martin H.