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Formula: Mn2+Fe3+2(PO4)2(OH)2.4H2O
Hydrated phosphate containing hydroxyl, arthurite group,
manganese-bearing mineral
Crystal System: Monoclinic
Specific gravity: 2.90 measured, 2.92 calculated
Hardness: 3 to 4
Streak: Light brown
Colour: Dark reddish brown, yellowish brown, yellow-orange, bright yellow
Luminescence: No fluorescence under UV
Environments
Localities
From the Hagendorf South Pegmatite, Hagendorf, Waidhaus, Neustadt an der Waldnaab District, Upper Palatinate, Bavaria,
Germany, earlshannonite was discovered on a specimen labeled as
rockbridgeite. On this specimen, bright yellow, divergent sprays of
earlshannonite form an encrustation on
rockbridgeite-frondelite
(CM 22.471-474).
The Emmons pegmatite, Greenwood, Oxford county, Maine, USA, is situated in a belt of metasedimentary rocks which
originated as marine sediments which were subsequently deformed and metamorphosed. The Emmons
pegmatite is an example of a highly evolved
boron-lithium-cesium-tantalum enriched
pegmatite. Earlshannonite occurs here, usually
associated with
hureaulite, strunzite,
phosphoferrite and
mitridatite
(R&M 94.6.506).
At the type locality, the Foote Lithium Co. Mine, Kings Mountain Mining District, Cleveland county, North Carolina,
USA, earlshannonite was found on the mine dumps as radial aggregates of crystals to 0.5 mm in a
pegmatite. On the type specimens, the
quartz matrix has a thin, dull green coating of
mitridatite, which is in turn coated by randomly distributed crystals and
crystal clusters of laueite, a
jahnsite-group mineral,
rockbridgeite and earlshannonite. Sequential growth relationships
are ambiguous, but earlshannonite is among the last species to form in the sequence of late-stage
secondary phosphates. The phosphate species are coated by
bulbous, irregular aggregates of a manganese oxide
(CM 22.471-474).
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