from The American Heritage® Dictionary of the English Language, 4th Edition
- 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 Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A feldspathoid mineral of silica-poor igneous, plutonic and volcanic rocks. Chemically, nepheline is a plagioclase feldspar with insufficient silica to satisfy the chemical bonds. Because of the unfilled bonds, nepheline weathers rapidly and can only be seen as inclusions in freshly broken rock.
from the GNU version of the Collaborative International Dictionary of English
- n. A mineral occuring at Vesuvius, in glassy hexagonal crystals; also elsewhere, in grayish or greenish masses having a greasy luster, as the variety elæolite. It is a silicate of aluminia, soda, and potash.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a whitish mineral consisting of sodium aluminum silicate or potassium aluminum silicate in crystalline form; 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.(American Heritage® Dictionary of the English Language, Fourth Edition)