Lazurite, which has the composition (Na,Ca)8[AlSiO4]6(SO4,S,Cl)2, is a mineral used as jade and in pigment-making. It belongs to the isometric crystal system and has a vitreous-waxy lustre, a granular structure, a dense texture, a Mohs hardness of 5–6, a specific gravity of 2.4–2.9, a refractive index of 1.5 and opaque to slightly translucent diaphaneity. Lazurite has a bright blue colour. Its complex colour hues and gold star flash make it a precious type of jade. As a pigment, it is called ‘gold spirit’, ‘Fu blue’, ‘Muslim blue’ or ‘cluster blue’. It was often used in ancient murals. Based on its composition and colour pattern, lazurite is categorised into four types in Chinese: (1) pure blue and gold stone; (2) blue gold; (3) gold wave; and (4) parturition stone. Lazurite mainly forms in contact zones between alkaline and carbonate rocks.