Fairfieldite

fairfieldite

collinsite

eosphorite

diadochite

Images

Formula: Ca2Mn2+(PO4)2.2H2O
Hydrated normal phosphate, fairfieldite group, forms a series with collinsite
Specific gravity: 3.08 to 3.11
Hardness: 3½
Streak: White
Colour: White, greenish white, light amber, salmon-yellow; colourless in transmitted light
Solubility: Soluble in acids
Environments

Pegmatites

Fairfieldite is an accessory mineral in granite pegmatites, associated with apatite, strunzite, diadochite, dickinsonite, stewartite, rockbridgeite, mitridatite, hureaulite, eosphorite, other iron-manganese phosphates, jahnsite, rhodochrosite, quartz and muscovite (HOM ). It is found as an alteration product of dickinsonite and as pseudomorphs after rhodochrosite (Mindat, Dana).

Localities

At the type locality, the Fillow Quarry, Branchville, Redding, Fairfield County, Connecticut, USA, fairfieldite occurs in a granite pegmatite associated with triploidite, reddingite, lithiophilite, fillowite, eosphorite and dickinsonite-(KMnNa) (Mindat, Dana).

At Berry quarry, Poland, Androscoggin county, Maine, USA, fairfieldite is found with rhodochrosite, eosphorite, reddingite and other manganese phosphates (Dana).

At the Emmons pegmatite, Greenwood, Oxford county, Maine, USA, fairfieldite is associated with hureaulite, vivianite and mitridatite (R&M 94.6.507).

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