Formula: LiMn2+(PO4)
Anhydrous normal phosphate, triphylite group and also forms a complete series with triphylite.
Specific gravity: 3.29 to 3.50
Hardness: 4
Streak: Colourless to greyish white
Colour: Reddish-brown, yellowish brown, golden-yellow, salmon-orange; colourless to light yellow, pink in transmitted light.
Solubility: Soluble in acids
Common impurities: Mg,Ca,Fe

Hydrothermal environments

Lithiophilite is a late-stage mineral in some complex granite pegmatites, usually primary and rarely secondary (HOM). It readily undergoes alteration with meteoric or hydrothermal solutions to other phosphate minerals with manganese predominant, such as sicklerite, triploidite, reddingite, eosphorite, fairfieldite, dickinsonite, and fillowite. Further oxidation (Mn2+ to Mn3+, associated with Fe2+ to Fe3+) yields purpurite - heterosite series minerals (Dana). All of these minerals are common associates, as well as rhodochrosite, spodumene, albite, beryl, amblygonite, hureaulite and graftonite (Dana).

In San Luis province, Argentina, lithiophilite has been found intergrown with beusite (AM 53.1804).

At the type locality, the Fillow Quarry, Branchville, Fairfield county, Connecticut, USA, lithiophilite occurs in a granite pegmatite (Mindat).

At the Emmons pegmatite, Greenwood, Oxford county, Maine, USA, lithiophilite occurs in pods to 45 cm across in the core and intermediate zone. Composite masses of lithiophilite, rhodochrosite and montebrasite are abundant. Some pods may have been converted to heterosite-purpurite by oxidising the manganese Mn and iron Fe and removing the lithium Li. The Emmons pegmatite is an example of a highly evolved boron-lithium-cesium-tantalum enriched pegmatite (R&M 94.6.510-511).

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