Tags: Chemical Substance, Mineral.
Lazurite is a tectosilicate mineral with sulfate sulfur and chloride with formula: (NaCa)8[(SClSO4OH)2(Al6Si6O24)]. It is a feldspathoid and a member of the sodalite group. Lazurite crystallizes in the isometric system although well formed crystals are rare. It is usually massive and forms the bulk of the gemstone lapis lazuli.Lazurite is a deep blue to greenish blue. The colour is due to the presence of Sā3 anions. It has a Mohs hardness of 5.0 to 5.5 and a specific gravity of 2.4.