Lazurite

Alumino-silicate mineral whose blue colour is due to a sulfide species and not copper

Lazurite, old name Azure spar is a tectosilicate mineral with sulfate, sulfur and chloride with the formula (Na,Ca)8[(S,Cl,SO4,OH)2|(Al6Si6O24)]. It is a feldspathoid and a member of the sodalite group. Lazurite crystallizes in the isometric system although well‐formed crystals are rare.

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