ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
ConchoidalWalter Schumann, Gemstones of the world (2001), ConchoidalWalter Schumann, Gemstones of the world (2001)
Ca 5(F,Cl)(PO 4) 3Arthur Thomas , Gemstones (2009)
SiO 2Walter Schumann , Gemstones of the world (2001)