gneiss
[ nahys ]
/ naɪs /
noun
a metamorphic rock, generally made up of bands that differ in color and composition, some bands being rich in feldspar and quartz, others rich in hornblende or mica.
Origin of gneiss
Borrowed into English from German around 1750–60
OTHER WORDS FROM gneiss
gneiss·ic, adjectiveWords nearby gneiss
Example sentences from the Web for gneiss
British Dictionary definitions for gneiss
gneiss
/ (naɪs) /
noun
any coarse-grained metamorphic rock that is banded and foliated: represents the last stage in the metamorphism of rocks before melting
Derived forms of gneiss
gneissic, gneissoid or gneissose, adjectiveWord Origin for gneiss
C18: from German
Gneis, probably from Middle High German
ganeist spark; related to Old Norse
gneista to give off sparks
Scientific definitions for gneiss
gneiss
[ nīs ]
A highly foliated, coarse-grained metamorphic rock consisting of light-colored layers, usually of quartz and feldspar, alternating with dark-colored layers of other minerals, usually hornblende and biotite. Individual grains are often visible between layers. Gneiss forms as the result of the regional metamorphism of igneous, sedimentary, or other metamorphic rocks.