Nepheline, also called nephelite (from Ancient Greek νεφέλη (nephélē) 'cloud'), is a rock-forming mineral in the feldspathoid group – a silica-undersaturated aluminosilicate, Na3KAl4Si4O16, that occurs in intrusive and volcanic rocks with low silica, and in their associated pegmatites.

Nepheline crystals are rare and belong to the hexagonal system, usually having the form of a short, six-sided prism terminated by the basal plane.

[5] An important determinative character of nepheline is the ease with which it is decomposed by hydrochloric acid, with separation of gelatinous silica (which may be readily stained by coloring matters) and cubes of salt.

[9] Notable outcrops of nepheline-bearing rocks are found on the Kola Peninsula; in Norway and South Africa; and at Litchfield, Maine; Magnet Cove, Arkansas; and Beemerville, New Jersey, in the United States.

[11] Elaeolite (a name given by M. H. Klaproth 1809, from Greek words for oil [ἔλαιον] and stone [λίθος]; German: Fettstein)[8] is a massive form of translucent nepheline with a darker color and greasy luster.

Nepheline produced as a byproduct of apatite mining in the Kola Peninsula has found uses in ceramics, leather, rubber, textiles, wood, and the oil industry.