Metaswitzerite

metaswitzerite

switzerite

vivianite

lithiophilite

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Formula: Mn2+3(PO4)2.4H2O
Hydrated normal phosphate, ludlamite group, manganese-bearing mineral
Crystal System: Monoclinic
Specific gravity: 2.95 measured, 3.18 calculated
Hardness: 2½
Streak: White
Colour: Light golden brown, pale pink, white
Environments

Pegmatites

Metaswitzerite occurs in granite pegmatites and in zinc-bearing phosphorus deposits. It forms by irreversible dehydration of switzerite on exposure to air. Associated minerals include switzerite, vivianite and scholzite (Mindat, HOM).

Localities

At the Emmons pegmatite, Greenwood, Oxford county, Maine, USA, switzerite and metaswitzerite occur rarely as patches of crystals to 2 mm in rhodochrosite and altered lithiophilite. The Emmons pegmatite is situated in a belt of metasedimentary rocks which originated as marine sediments which were subsequently deformed and metamorphosed. The Emmons pegmatite is an example of a highly evolved boron-lithium-cesium-tantalum enriched pegmatite (R&M 94.6.516).

At the type locality, the Foote Lithium Co. mine, Kings Mountain Mining District, Cleveland county, North Carolina, USA, the local rocks are thin-layered amphibolite and muscovite gneiss and schist. The mine is a large open pit in a swarm of granite pegmatites of uniform composition containing roughly 32% quartz, 41% feldspars, 20% spodumene, 6% muscovite and l% other minerals. Numerous fractures and seams cut the pegmatites; many contain quartz and albite crystal druses. Other minerals, including apatite, vivianite, fairfieldite, pyrite, rhodochrosite-siderite and laumontite are present locally.
The mineralisation of the seams probably took place during the last stages of crystallisation of the pegmatite. Metaswitzerite is found as masses and crystals in some of the seams. It is usually associated, and sometimes intergrown, with vivianite. Both metaswitzerite and vivianite are abundant as very thin films coating fractures (AM 52.1595-1602).

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