Hydrocalumite

hydrocalumite

ettringite

afwillite

portlandite

Images

Formula:Ca₄Al₂(OH)₁₂(Cl,CO₃,OH)₂.4H₂O
Hydroxide, hydrocalumite group
Crystal System: Monoclinic
Specific gravity: 2.15 measured, 2.15 calculated
Hardness: 3
Streak: White
Colour: Colourless to light green
Environments

Metamorphic environments
Hydrothermal environments

Hydrocalumite is a late-stage hydrothermal mineral in skarn formed from contact metamorphism of limestone (Webmin). Associated minerals include afwillite, portlandite, ettringite, larnite, plombièrite, grossular variety hydrogrossular and calcite (HOM).

Localities

At Boisséjour, Beaumont, Puy-de-Dôme, Auvergne-Rhône-Alpes, France, hydrocalumite occurs with ettringite (Dana).

At the type locality, Scawt Hill, Larne, County Antrim, Ulster, Northern Ireland, UK, hydrocalumite occurs in vugs in larnite rock with afwillite, portlandite and ettringite (Dana, AM 20.316).

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