Uneven-Conchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001)
Conchoidal, Conchoidal, Gemstones of the world (2001) More from other references
The chief constituent Lapis Lazuli is Lazurite, with the following chemical formula: (Na,Ca)8Al6Si6O24(S,SO)4
SiO 2 · nH 2OGemdat.org , Management Team (2012)