A relatively rare blue, violet-blue, or greenish-blue translucent mineral, Na4−5 Al3 Si3 O12 S, the chief component of lapis lazuli.
A very rare, hard, bluish, crystalline mineral, (Na,Ca)7(Al,Si)12(O,S)24[SO4,Cl2(OH)2]2, that is the main component of lapis lazuli.
(mineralogy) A mineral of metamorphosed limestones. Lazurite forms the gemstone lapis lazuli, and crushed lazurite provided the ultramarine color in artists' paint of the old masters. Sodalite and lazurite form the sodalite group of silicate minerals. Chemical composition: Sodium aluminum silicate with sulphur, Na4-5Al3Si3O12S.