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Formula: NaMgF3
Halide, perovskite group
Specific gravity: 3.03 measured, 3.06 calculated (?3.08)
Hardness: 4½
Streak: White
Colour: Colourless, cream, pink, red, brown
Solubility: Insoluble in water, soluble in acids
Environments
Plutonic igneous environments
Pegmatites
Hydrothermal environments
Localities
At the Poudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada, neighborite
occurs in cavities in pegmatite and
hornfels in an alkalic
gabbro-syenite complex
(HOM).
At Gjerdingselva, Lunner, Viken, Norway, neighborite occurs in miarolitic cavities in peralkaline
granite, as cube-like, colourless, pale yellow, or brownish crystals up to
1 mm in size, commonly displaying polysynthetic twinning striations. Associated minerals in the miarolitic cavities include
quartz, aegirine,
rhodochrosite, zircon,
fluorite, gagarinite,
monazite-(Ce), galena,
sphalerite, molybdenite and
brookite. Neighborite is a late-stage, low-temperature (<300oC)
hydrothermal mineral
(AM 91.1457).
In the Ural mountains, Russia, neighborite occurs in metamorphosed tuff
and clayey carbonate sediments
(HOM).
At the type locality, the Sun Haverstrite Well, Uintah County, Utah, USA, neighborite occurs as cream-coloured or
clear, colourless octahedral crystals. Such crystals were obtained from well cuttings at various depths. Besides fragments
of oil-bearing dolomitic shale, the
cuttings contain barytocalcite and
pyrite. The total amount of neighborite obtained is less than thirty milligrams
(AM 46.379-393).
At the South Ouray No. 1 well, Ouray, Uteland Knoll Mining District, Uintah county, Utah, USA, neighborite was found
as clusters of pink and brown rounded grains in a dark brown to greyish black, aluminium-deficient
dolomitic oil shale. It is associated
with burbankite, nahcolite,
wurtzite, barytocalcite,
garrelsite, pyrite,
calcite and quartz. Cores from the well at
a depth somewhere between 1700 and 2300 feet consist of layers of fine-grained dark brown to black
dolomitic oil shale interbedded with
layers of coarsely crystalline material of barytocalcite
and nahcolite. Most of the crystals of neighborite occur at the top of the
fine-grained shale layer that consists essentially of
dolomite and quartz with a minor trace of
feldspar. Some rounded neighborite occurs in discrete grains as inclusions
in crystals of barytocalcite in the coarsely crystalline layers
(AM 46.379-393).
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