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Sicklerite was DISCREDITED as a mineral species in 2023, and is now considered to be a variety of
lithiophilite
Formula: LiMn2+(PO4)
Anhydrous phosphate, triphylite group, forms a series with
ferrisicklerite, lithium-
and manganese- bearing mineral
Crystal System: Orthorhombic
Specific gravity: 3.2 to 3.4 measured, 3.54 calculated
Hardness: 4
Streak: Light ochre brown
Colour: Dark brown to yellow-brown
Solubility: Soluble in acids
Environments
Sicklerite is found in granite
pegmatites, where it occurs only as a late-stage
alteration product of triphylite and
lithiophilite, commonly as rims around partly altered masses
(Mindat, HOM).
Localities
At the type locality, the Stewart Mine, Pala, San Diego county, California, USA, sicklerite occurs in a
lithium-bearing
pegmatite associated with hureaulite,
stewartite, phosphosiderite,
jahnsite and phosphosiderite
(Dana, Mindat, HOM).
At the Emmons pegmatite, Greenwood, Oxford county, Maine, USA, sicklerite occurs only as massive material formed
by the oxidation of lithiophilite. The Emmons
pegmatite is an example of a highly evolved
boron - lithium -
cesium - tantalum
enriched pegmatite
(R&M 94.6.515).
Alteration
Sicklerite alters to the heterosite -
purpurite series by oxidation of the Mn2+ to Mn3+ and
leaching of the lithium
(Mindat).
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