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.

Nearby words

gnatty, gnaw, gnawing, gnawn, gnc, gneiss, gneissoid, gnetophyte, gniezno, gnma, gnoc

Origin of gneiss

Borrowed into English from German around 1750–60

Related forms

gneiss·ic, adjective

Can be confused

gneiss nice (see usage note at nice)

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for gneiss

In the centre of a lovely valley rises a conical rock of gneiss, protruding to the height of 200 feet or more.
Round About the Carpathians|Andrew F. Crosse
Hence the origin of the primary or crystalline strata,—gneiss, mica-schist, and the rest.
A Manual of Elementary Geology|Charles Lyell.
The rock was found by Watson to be gneiss, rich in mica, felspar and garnets.
The Home of the Blizzard|Douglas Mawson
The rocks, like those where we landed last night, were grey granite and gneiss.
Narrative of an Expedition to the Shores of the Arctic Sea in 1846 and 1847|John Rae

It is composed of gneiss, curiously crossed in every direction by veins of quartz.
Forest Life and Forest Trees: comprising winter camp-life among the loggers, and wild-wood adventure.|John S. Springer

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

gneissic, gneissoid or gneissose, adjective

Word Origin for gneiss

C18: from German Gneis, probably from Middle High German ganeist spark; related to Old Norse gneista to give off sparks

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science 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.