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Formula: LiMn2+(PO4)
Anhydrous normal phosphate, triphylite group,
lithium- and manganese-
bearing mineral, 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.
Crystal System: Orthorhombic
Specific gravity: 3.29 to 3.50 measured, 3.433 calculated
Solubility: Soluble in acids
Common impurities: Mg,Ca,Fe
Environments:
Pegmatites
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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