Uneven-Conchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001)
Gemstones of the world (2001), UnevenWalter Schumann, Gemstones of the world (2001)
The chief constituent Lapis Lazuli is Lazurite, with the following chemical formula: (Na,Ca)8Al6Si6O24(S,SO)4
LiAlSi2O6