ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Uneven-Conchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001)
Ca 5(F,Cl)(PO 4) 3Arthur Thomas , Gemstones (2009)
The chief constituent Lapis Lazuli is Lazurite, with the following chemical formula: (Na,Ca)8Al6Si6O24(S,SO)4