Nepheline Syenite


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nepheline syenite

[′nef·ə‚lēn ′sī·ə‚nīt]
(petrology)
A phaneritic plutonic rock with granular texture, composed largely of alkali feldspar, nepheline, and dark-colored materials.

Nepheline Syenite

 

a magmatic alkali rock composed of nepheline, alkali feldspars (sanidine, orthoclase, or microcline), biotite, and alkali amphiboles and pyroxenes. It also contains zirconium-bearing silicates (zircon, eudialyte) and titanium-bearing silicates (sphene, lamprophyllite), as well as minerals containing F, P2O5, CO2 (cancrinite, calcite, apatite, fluorite) and rare earths (rinkolite, loparite). Nepheline syenite contains 50–56 percent SiO2, 19–24 percent Al2O3, a small quantity of Ca and Mg, and 15–17 percent K and Na.

There are numerous varieties of nepheline syenites, including (1) chibinites, greenish gray coarse-grained pyroxene nepheline syenites, with pegmatic texture; (2) rischorites, yellowish gray or greenish gray rocks with poikilitic texture; (3) lujauvrites, greenish black rocks with marked trachytic texture; (4) miascites, micaceous lamellar nepheline syenites found in the Urals; (5) mariupolites, distinctive albite-rich nepheline syenites; and (6) saibarites, melanocratic nepheline syenites found in Siberia and elsewhere. In addition to the USSR, nepheline-syenite deposits are also found in the vicinity of Oslo, Norway, and in southern Greenland, in Canada, in southern Africa, and on Madagascar. Nepheline syenites occur in association with apatites (Kola Peninsula), graphite (Saian Mountains), cryolite (Greenland), and a number of rare elements.

REFERENCES

Kupletskii, B. M. Formatsiia nefelinovykh sienitov SSSR. Moscow-Leningrad, 1937.
Kupletskii, B. M. “K voprosu o kolichestvenno-mineralo-gicheskom sostave fel’dshpatoidnykh porod.” Dokl. AN SSSR: Novaia seriia, 1946, vol. 52, no. 3.
References in periodicals archive ?
The chief metallic mineral resources include: gold, zinc, copper and tin-tungsten, while the chief non-metallic resources include: phosphate, high-grade silica sand, feldspar and nepheline syenite, kaolin, basalt and scoria, gypsum and anhydrite, limestone and dolomite, ornamental stone and quartz.
Among the additives options that prevent thin plastic layers from sticking to each other, 'Talc, nepheline syenite, and DE have been the incumbent high-performance antiblock minerals in plastic films," says John Flurley, president and CEO of Trinity Resources.
Transparent Ferro Frit # 3195 50 Custer feldspar 21 Flint 325x 16 EPK day 8 Whiting 5 Bentonite 2 Zam #15 Opaque Matt Nepheline syenite 270x 45 Whiting 18 EPK day 20 Flint 325x 5 Zinc oxide 12 Bentonite 2
distributor is Maroon Group, Avon, Ohio) is said to combine the best attributes of talc, nepheline syenite (NS), and diatomaceous earth (DE).
Other resources are Nepheline Syenite, phosphates, gemstones, and metallic minerals including gold and base metals and variety of other industrial minerals.
1 to 5 parts per hundred parts resin (phr) of one or more wax and from 75 phr to 200 phr of one or more extenders wherein the one or more extenders is selected from the group consisting of barium sulfate, titanium dioxide, iron oxides, crystalline silica (quartz), calcium metasilicate, soda lime glass spheres, magnesium silicate, nepheline syenite, muscovite mica, diatomaceous earth, kaolin clay and calcium carbonate.
UC RUSAL's nepheline syenite production was 4,662 thousand tonnes in 2013, as compared to 4,947 thousand tonnes in 2012 (a decrease of 6%).
This stage suggests creation of small mining enterprises by 2020 on the basis of international experience, enhancement of investment attractiveness of quartz, beryllium, aluminum, nepheline syenite, iron ore fields and other kinds of non-traditional minerals.
8:30-9:00 am--Rheological Characterization of a Solvent-based Oil-modified Urethane Floor Coating Containing Nepheline Syenite Mineral: Impact of Select Rheology Modifiers on Suspension Behavior--Ron Obie, Wood Coatings Research Group
the anorogenic nepheline syenite intrusion of the same name, are tabled below.
62 Ga--emplacement of small post-tectonic granite, nepheline syenite, and carbonatite intrusions, and protracted post-metamorphic hydrothermal activity focused mainly along fault zones.
2], is often blue but may be white or pink, occurs in both volcanic and plutonic rocks of the nepheline syenite family.