Is Nepheline a Gemstone?

Nepheline is an extremely rare gem because clean, facetable crystals are very rare and usually very small. The hardness is 5.5 – 6, and the specific gravity 2.55 – 2.66. ... Colored varieties of Nepheline are called Elaeolite.

What kind of mineral is nepheline?

Nepheline, also called nephelite, or eleolite, the most common feldspathoid mineral, an aluminosilicate of sodium and potassium [(Na,K)AlSiO₄]. It is sometimes used as a substitute for feldspars in the manufacture of glass and ceramics.

What is nepheline rock?

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.