ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Uneven-Conchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001)
(Ca,Cr)MgSi 2O 6Gemdat.org , Management Team (2012)
The chief constituent Lapis Lazuli is Lazurite, with the following chemical formula: (Na,Ca)8Al6Si6O24(S,SO)4