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 ?
Focus would be made to take advantage of NephelineSyenite, phosphates, gemstones and metallic minerals including gold and base metals and other variety of industrial minerals and reduce damages of marble and other stones during excavation process.
Table 6: World Historic Review for Feldspar and NephelineSyenite by Geographic Region - US, Canada, Japan, Europe,Asia-Pacific (excluding Japan), Middle East & Africa, andLatin American Markets Independently Analyzed with AnnualConsumption Figures in Thousand Metric Tons for Years 2003through 2008(includes corresponding Graph/Chart) II-32
Table 9: World Historic Review for Feldspar and NephelineSyenite in Glass by Geographic Region -US, Canada, Japan,Europe, Asia-Pacific (excluding Japan), Middle East & Africa,and Latin American Markets Independently Analyzed with AnnualConsumption Figures in Thousand Metric Tons for Years 2003through 2008(includes corresponding Graph/Chart) II-35
Table 13: World 15-Year Perspective for Feldspar and NephelineSyenite in Ceramics by Geographic Region - PercentageBreakdown of Volume Consumption for US, Canada, Japan, Europe,Asia-Pacific (excluding Japan), Middle East & Africa, andLatin American Markets for Years 2003, 2011 & 2017(includescorresponding Graph/Chart) II-39
Table 15: World Historic Review for Feldspar and NephelineSyenite in Fillers by Geographic Region - US, Canada, Japan,Europe, Asia-Pacific (excluding Japan), Middle East & Africa,and Latin American Markets Independently Analyzed with AnnualConsumption Figures in Thousand Metric Tons for Years 2003through 2008(includes corresponding Graph/Chart) II-41
Table 19: World 15-Year Perspective for Feldspar and NephelineSyenite in Other End-Uses by Geographic Region - PercentageBreakdown of Volume Consumption for US, Canada, Japan, Europe,Asia-Pacific (excluding Japan), Middle East & Africa, andLatin American Markets for Years 2003, 2011 & 2017(includescorresponding Graph/Chart) II-45III.
Table 30: US 15-Year Perspective for Feldspar and NephelineSyenite by End-Use Segment - Percentage Breakdown of VolumeConsumption for Glass, Ceramics, Fillers and Other End-UseMarkets for Years 2003, 2011 & 2017 (includes correspondingGraph/Chart) III-7
Table 51: German Historic Review for Feldspar and NephelineSyenite by End-Use Segment - Glass, Ceramics, Fillers andOther End-Use Markets Independently Analyzed with AnnualConsumption Figures in Thousand Metric Tons for Years 2003through 2008(includes corresponding Graph/Chart) III-29
Table 57: UK Historic Review for Feldspar and NephelineSyenite by End-Use Segment - Glass, Ceramics, Fillers andOther End-Use Markets Independently Analyzed with AnnualConsumption Figures in Thousand Metric Tons for Years 2003through 2008(includes corresponding Graph/Chart) III-36