Collection: Lazurite

(Old note): Often there is minor K substituting for Na.
The IMA takes the ideal formula with S as the dominant anion and not sulfate, from Hassan et al. (1985), but even that reference indicates that sulfate is dominant, making lazurite either a sulfide-rich variety of Hauyne or just a theoretical end member of a series with hauyne.
(New note): Formerly given as Na₆Ca₂(Al₆Si₆O₂₄)(SO₄,S,S₂,S₃,Cl,OH)₂.
Finally, redefined with the formula given above.