nepheline

neph·e·line

N0060900 (nĕf′ə-lēn′, -lĭn) also neph·e·lite (-līt′)n. A mineral of sodium-aluminum or potassium-aluminum silicate, occurring worldwide in igneous rocks and used in the manufacture of ceramics and enamels.

[From Greek nephelē, cloud (because its fragments become cloudy when placed in nitric acid); see nebh- in Indo-European roots.]

neph′e·lin′ic (-lĭn′ĭk) adj.

nepheline

(ˈnɛfɪlɪn; -ˌliːn) or

nephelite

n (Minerals) a whitish mineral consisting of sodium potassium aluminium silicate in hexagonal crystalline form: used in the manufacture of glass and ceramics. Formula: (Na,K)(AlSi)2O4[C19: from French néphéline, from Greek nephelē cloud, so called because pieces of it become cloudy if dipped in nitric acid]

neph•e•line

(ˈnɛf ə lɪn)

also neph•e•lite

(-ˌlaɪt)

n. a feldspathoid mineral, sodium potassium aluminum silicate, Na₃KAl₄Si₄O₁₆, occurring in basaltic lavas. [1805–15; < French]

Thesaurus

Noun

nepheline - a whitish mineral consisting of sodium aluminum silicate or potassium aluminum silicate in crystalline form; used in the manufacture of ceramics and enamelsnephelitemineral - solid homogeneous inorganic substances occurring in nature having a definite chemical compositionnephelinite - an igneous rock consisting of nepheline and pyroxene

Nepheline

enUK

nepheline

[′nef·ə‚lēn] (mineralogy) A mineral of variable composition, with its purest state represented by the formula NaAlSiO₄; calcium, magnesium, iron (Fe²⁺and Fe³⁺), and titanium are usually present in only minor or trace amounts.

Nepheline

a mineral of the tectosilicate class with chemical composition KNa₃ [AlSiO₄]_4. It usually contains an excess of Si and admixtures of Ca, Mg, and, more rarely, Fe, Be, Cl, H₂O, and Ga. The structure of nepheline is based on a slightly distorted structure of tridymite, whose large holes (spaces) contain alkaline cations. The arrangement of the (Si, Al) tetrahedrons distorts the structure in such a way that it has no plane of symmetry.

Nepheline crystallizes in the hexagonal system to form massive grainy aggregates and, more rarely, small prismatic crystals. It has a hardness of 5.5–6 on Mohs’ scale and a density of 2,550–2,650 kg/m³. The cleavage is imperfect; the luster varies from vitreous to greasy. The mineral is usually colorless, pink, gray, or greenish.

Nepheline is readily soluble in acid, yielding flocculent silica. It is a principal mineral constituent of alkali rocks (nepheline syenites and their pegmatites). Nepheline alters to sodalite, cancrinite, and zeolites upon the action of postmagmatic solutions. Under supergenic conditions, it converts to hydromica, mont-morillonite, and halloysite; lateritic weathering causes nepheline to alter to gibbsite.

In the USSR, major nepheline deposits are located on the Kola Peninsula, in the Il’men’ Mountains (Urals), in Krasnoiarsk Krai, and in the Alai Range. Other deposits are found in Greenland, Norway, Sweden, the Federal Republic of Germany, Kenya, and elsewhere. In the USSR, a process has been developed permitting an efficient utilization of the mineral whereby aluminum, soda, and other products are obtained. Nepheline is also used in glassmaking, in the preparation of silica gel, and in agriculture as a fertilizer for acidic soils.

REFERENCES

Betekhtin, A. G. Kurs mineralogii, 2nd ed. Moscow, 1956.
kostov, I. Mineralogiia. Moscow, 1971. (Translated from English.)

M. D. DORFMAN

nepheline

neph·e·line

nepheline

nephelite

neph•e•line

also neph•e•lite

Nepheline

nepheline

Nepheline

REFERENCES

nepheline

Synonyms for nepheline

noun a whitish mineral consisting of sodium aluminum silicate or potassium aluminum silicate in crystalline form

Synonyms

Related Words