(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.
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