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Formula: Fe2+Fe3+2(PO4)2(OH)2.4H2O
Hydrated phosphate containing hydroxyl, arthurite group
Crystal System: Monoclinic
Specific gravity: 2.87 measured, 2.85 calculated
Hardness: 3
Colour: Yellow-brown, green-brown
Common impurities: Mn
Environments:
Pegmatites
Hydrothermal environments
Whitmoreite occurs as a secondary mineral in complex
zoned granite
pegmatites, associated with
siderite, triphylite,
ludlamite, strunzite,
laueite, beraunite,
mitridatite, ushkovite and
iron-manganese oxides
(HOM, Mindat). It is a hydrothermal alteration product of triphylite
in cavities in quartz-bearing
pegmatites
(Webmin).
Localities
At the type locality, the Palermo No. 1 Mine, Groton, Grafton county, New Hampshire, USA, whitmoreite occurs as
thin acicular crystals to 2.0 mm in length, usually grouped as fans and sprays and almost invariably perched upon
siderite rhombohedra in open cavities in the
quartz-bearing pegmatite.
Earlier in the paragenesis are quartz crystals,
siderite and occasional ludlamite;
the later species include strunzite,
laueite, beraunite,
mitridatite and manganese and
iron oxyhydroxides. The siderite
paragenesis derived from the alkali-leaching and late stage carbonation of parent
triphylite
(AM 59.900-905).
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