Haüyne

hauyne

lazurite

leucite

melilite

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Formula: Na3Ca(Si3Al3)O12(SO4)
Tectosilicate (framework silicate), feldspathoid, sodalite group, forms a discontinuous solid solution with nosean and with sodalite (Dana)
Specific gravity: 2.44 to 2.5
Hardness: 5½ to 6
Streak: Very pale blue to white. The sulphide-rich variety of haüyne commonly incorrectly called "lazurite" is bright blue
Colour: Blue, white, grey, yellow, green, pink
Solubility: Gelatinises with acids
Common impurities: K
Environments:

Igneous environments
Metamorphic environments

Haüyne occurs in phonolite and related leucite- or nepheline- rich igneous rocks; less commonly in nepheline-free volcanic rocks. Associated minerals include nepheline, leucite, titanium-bearing andradite, melilite, augite, sanidine, biotite, calcite, phlogopite and apatite (HOM). Also in skarn (contact metamorphism) and marble (regional metamorphism) (Mindat, Dana).

Localities

There are two co-type localities, Monte Somma, Somma-Vesuvius Complex, Naples, Campania, Italy, and the Northwestern Lake Nemi Shore, Nemi, Metropolitan City of Rome Capital, Lazio, Italy. At the type localities haüyne occurs in volcanic rocks rich in sodium and potassium (Mindat).

At the Cripple Creek Mining District, Teller county, Colorado, USA, haüyne is common in small quantities as phenocrysts in phonolite and monchiquite (Minrec 36.2.173).

At the Winnett sill, Petroleum county, Montana, USA, haüyne occurs in nepheline lamprophyre with melilite, phlogopite and apatite (Dana).

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