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Formula: (Al,Li)(Mn4+,Mn3+)O2(OH)2
Hydroxide, lithium- and
manganese- bearing mineral
Crystal System: Trigonal
Specific gravity: 3.14 to 3.37
Hardness: 3
Streak: Dark grey to black
Colour: Blue to black
Environments
Pegmatites
Sedimentary environments
Hydrothermal environments
Lithiophorite is a relatively common constituent of “wad” (a mixture of black
manganese oxides) in the oxidised zones of hydrothermal ore deposits and
sedimentary manganese deposits; in banded iron formations; from
lithium-rich granite
pegmatites; in some
lateritic soils and bauxites.
Associated minerals include cryptomelane,
hollandite, braunite,
nsutite, pyrolusite,
bixbyite-(Mn), gibbsite,
kaolinite and hematite
(HOM). In wad, lithiophorite is associated with asbolane,
vernadite, birnessite,
cryptomelane and others
(Dana).
Localities
The type locality is Spitzleithe, Schneeberg, Erzgebirgskreis, Saxony, Germany.
At the Postmasburg manganese field, Northern Cape, South Africa, the lithiophorite specimens are coarsely
crystalline, the diameters of the individual grains varying from a few millimetres to about a centimetre. In part they
are botryoidal and show protruding crystals. Braunite, partly altered
to psilomelane, is found in the cores of the botryoidal masses and it
appears as if the lithiophorite were deposited on the braunite in
cavities.
The order of crystallisation appears to be braunite →
bixbyite-(Mn) → lithiophorite. Part of the
braunite however, like the
psilomelane, may have been formed through the alteration of earlier
minerals and this braunite would therefore be younger than the
lithiophorite.
The lithiophorite from the Bishop farm occurs as layers, a few millimetres thick, in a laminated
psilomelane-hematite ore
(AM 30.629-634).
At Charlottesville, Albemarle county, Virginia, USA, there is a lithiophorite-rich vein of milky vitreous to
white saccaroidal quartz, full of planar fractures upon which
lithiophorite has been deposited. Usually this mineral only coats the surfaces, instead of completely filling
the fractures. Some cavities in the quartz contain
kaolinite. Porcellaneous reddish-brown
halloysite-7Å clay is
intimately associated with the lithiophorite crusts, and also fills fractures in the
quartz vein and associated rocks
(AM 52.1545-1549).
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