ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001)
Be 3Al 2Si 6O 18Ulrich Henn and Claudio C.
Ca 5(PO 4) 3FAnthony et al , Handbook of mineralogy (2001)