Whitmoreite

minerals

siderite

triphylite

mitridatite

Images
Formula: Fe2+Fe3+2(PO4)2(OH)2.4H2O
Hydrated phosphate containing hydroxyl, arthurite group
Specific gravity: 2.87
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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