from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A rare igneous rock consisting essentially of nepheline and augite.
from The Century Dictionary and Cyclopedia
- n. A phanerocrystalline igneous rock composed of nephelite and pyroxene with small amounts of apatite, titanite, and ivaarite. It corresponds in composition to nephelinite, and occurs in dikes associated with nephelite-syenite.
Derived from the first syllable of the Finnish words Ii-vaara, Iijoki, etc., common as geographical names in Finland, and Ancient Greek λίθος (lithos, "a stone"). (Wiktionary)