Nepheline Value, Price, and Jewelry Information


Nepheline
By Andrew Silver, USGS.Materialscientist at en.wikipedia [Public domain or Public domain], from Wikimedia Commons

A variety called elaeolite is red, green, brown, or gray, massive or in crystals filled with minute inclusions. These inclusions produce a sheen that yields a catseye effect in cabochons. Facetable nepheline is a great rarity, and very few gems have been cut, always in the 1-2 carat range or smaller.

Nepheline Value

The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.

Nepheline Information

DataValue
NameNepheline
VarietiesElaeolite
Scientific NameNepheline
Crystallography Hexagonal. Crystals stumpy, sometimes very large; massive, compact; in grains.
Colors Colorless, white, gray, yellowish, greenish, bluish, dark green, brick red, brownish red.
Luster Vitreous to greasy.
Fracture Subconchoidal. Brittle.
Hardness 5.5-6.
Specific Gravity 2.55-2.66
Birefringence 0.004.
Cleavage Indistinct.
Dispersion Low.
Stone SizesCabochons of nepheline have been cut in various sizes; crystals, especially those from Canada, can reach enormous size but are not attractive. Faceting material is extremely rare and very small.
Luminescence Medium light blue (Germany) or medium dull orange (Ontario) in LW.
Spectral Not diagnostic.
Formula(Na,K)AlSiO4.

Optics: o = 1.529-1.546; e= 1.526-1.542.

Uniaxial (-).

Occurrence: Plutonic and volcanic rocks; pegmatites associated with nepheline syenites.

Julienhaab district, Greenland; Langesundsfford, Norway;

Germany; Finland; USSR; Burma; Korea.

Various localities in the United States, especially Maine and Arkansas.

Ontario, Canada: crystals up to 15 inches long (non-gemmy).

Vesuvius, Italy: small, glassy transparent grains.

Comments: A variety called elaeolite is red, green, brown, or gray, massive or in crystals filled with minute inclusions. These inclusions produce a sheen that yields a catseye effect in cabochons. Facetable nepheline is a great rarity, and very few gems have been cut, always in the 1-2 carat range or smaller.

Name: From a Latin word meaning cloud because it becomes cloudy when immersed in acid. Elaeolite is from a Latin Word for oil because of its greasy luster.