This sample of lazurite is displayed in the Smithsonian Museum of Natural History. Lazurite is a has the composition (Na,Ca)8[(S,SO4,Cl2)|Al6Si6O24]. The sample above about 30 cm across and is described as lazurite with calcite. The lazurite crystal at left is about 2 cm across.
The largest of these crystals is about 2.5 cm across. All these samples are from Badakhshan, Afghanistan.