ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001)
SiO 2 + H 2OUlrich Henn and Claudio C.
Ca 5(PO 4) 3FAnthony et al , Handbook of mineralogy (2001)