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Formula: ZnMn2+Fe2+2Fe3+(PO4)34(OH)24(H24O)74.2H24O
Hydrated phosphate, schoonerite group,
zinc- and
manganese- bearing mineral
Specific gravity: 2.87 to 2.92 measured, 2.79 calculated
Hardness: 4
Streak: Pale brown
Colour: Pale tan to brown, greenish brown, reddish brown to bronzy on weathered surface
Luminescence: Not fluorescent in UV
Solubility: Rapidly soluble in hydrochloric acid
Environments
Pegmatites
Hydrothermal environments
Localities
At the type locality, the Palermo No. 1 Mine, Groton, Grafton County, New Hampshire, USA, numerous posphate pods are
found in the palermo pegmatite. Schoonerite is a very
sparse but widely distributed phase, occurring locally in minute quantities. It is the latest product in the assemblage;
associated phases include mitridatite,
laueite, strunzite,
whitmoreite and
iron-manganese oxyhydroxides. It has
been noted as local patches and mats coating thin fracture surfaces cutting
whitlockite-apatite rock,
usually upon a thin black base of the oxides. It also occurs as scattered to bunched thin, friable laths in small open
cavities in siderite, ludlamite and
messelite, and in solution cavities in
vivianite, which schoonerite replaces. Schoonerite is thought to
be a product of low-temperature hydrothermal attack, weathering and oxidation of more reduced phases such as
triphylite, ludlamite,
vivianite and sphalerite, all of
which occur as common constituents of the pods.
Two samples illustrate different paragenetic settings for schoonerite:
One is a mass of dense fine-grained whitlockite and
hydroxylapatite. Granular
siderite occurs along one side of the mass. Implanted upon solution cavities in
the whitlockite and apatite are
radial aggregates of childrenite, warty brown
jahnsite, and a film of dull green
mitridatite. The schoonerite occurs as copper-red glistening scales
and mats across the surface, the latest mineral in the sequence.
The second sample is the type sample itself, which came from a triphylite
pod; portions of the triphylite, especially along the periphery, are
completely replaced by granular siderite, coarse patches of
ludlamite, and remnant arrojadite.
Cavities in the sample are studded with lustrous siderite rhombohedra,
bipyramids of quartz, colourless cockscomb aggregates of
messelite, and pale blue laths of
vivianite. Upon these are perched radial sprays of
whitmoreite, orange laths of
jahnsite, a dull green layer of
mitridatite, and thin laths of the schoonerite. The sequence is
triphylite →arrojadite
→ludlamite →siderite
→messelite →vivianite
→mitridatite →
rockbridgeite →jahnsite
→whitmoreite →schoonerite. The schoonerite is
brown to copper-red and occurs as isolated laths to bunches of flattened strawlike aggregates up to 2 mm in length.
The limited occurrence of schoonerite may result from the fact that few
pegmatites carry significant quantities of the
zinc minerals necessary for its production
(AM 62.246-249).
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