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gneiss

[ nahys ]
/ naɪs /
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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. 2021

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, 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

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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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