gneiss

[ nahys ]

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.

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Origin of gneiss

Borrowed into English from German around 1750–60

Other words from gneiss

gneissic, adjective

Words that may be confused with gneiss

gneiss , nice

Words Nearby gneiss

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use gneiss in a sentence

gneiss is a similar mixture, but characterised by the predominance of mica, and by its banded structure.
Elements of Agricultural Chemistry | Thomas Anderson
A course gneiss is the predominant rock, but is associated with garnetiferous mica-schists and much intrusive granite.
Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 | Various
The former—mostly gneiss—is far more rugged and interesting, and there is infinitely more of the latter.
Mount Everest the Reconnaissance, 1921 | Charles Kenneth Howard-Bury
The tertiary formation is followed by an azoic formation of gneiss, mica slate, and phylada with large intrusions of granite.
Guatemala, the country of the future | Charles M. Pepper
Hannam operated the forge, and picks and drills were sent along for pointing; an outcrop of gneiss serving as an anvil.
The Home of the Blizzard | Douglas Mawson

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

Origin of gneiss

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

Derived forms of gneiss

gneissic, gneissoid or gneissose, adjective

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

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.

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