Neighborite

neighborite

barytocalcite

nahcolite

gagarinite

Images

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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