Lithiophorite

lithiophorite

cryptomelane

hollandite

braunite

Images

Formula: (Al,Li)(Mn4+,Mn3+)O2(OH)2
Oxide/hydroxide, lithium- and manganese- bearing mineral
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, 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 braunitebixbyite-(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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