AskDefine | Define gneiss

Dictionary Definition

gneiss n : a laminated metamorphic rock similar to granite

User Contributed Dictionary



From Gneiss, from gneist, from gneisto.


  • , /ˈnaɪs/, /naIs/
  • Rhymes with: -aɪs



  1. A common and widely-distributed metamorphic rock having bands or veins.


common and widely-distributed metamorphic rock

Extensive Definition

Gneiss () is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from preexisting formations that were originally either igneous or sedimentary rocks. Gneissic rocks are usually medium to coarse foliated and largely recrystallized but do not carry large quantities of micas, chlorite or other platy minerals. Gneisses that are metamorphosed igneous rocks or their equivalent are termed granite gneisses, diorite gneisses, etc. However, depending on their composition, they may also be called garnet gneiss, biotite gneiss, albite gneiss, etc. Orthogneiss designates a gneiss derived from an igneous rock, and paragneiss is one from a sedimentary rock. Gneissose is used to describe rocks with properties similar to gneiss.
Gneiss resembles schist, except that the minerals are arranged into bands. Sometimes it is difficult to tell the difference between gneiss and a schist because some gneiss appears to have more mica than it really does. This is especially true with mica-rich parting planes.
The etymology of the word "gneiss" is disputed. Some sources say it comes from the Middle High German verb gneist (to spark; so called because the rock glitters) and has occurred in English at least since 1757. Other sources claim the root to be an old Saxon mining term that seems to have meant decayed, rotten, or possibly worthless material.


Blatt, Harvey and Robert J. Tracy, 1996, Petrology: Igneous, Sedimentary and Metamorphic, 2nd ed., pp. 359-365, Freeman, ISBN 0-7167-2438-3
gneiss in Catalan: Gneis
gneiss in Czech: Rula (hornina)
gneiss in Danish: Gnejs
gneiss in German: Gneis
gneiss in Estonian: Gneiss
gneiss in Spanish: Gneis
gneiss in Esperanto: Gnejso
gneiss in Basque: Gneiss
gneiss in Persian: گنیس
gneiss in French: Gneiss
gneiss in Korean: 편마암
gneiss in Croatian: Gnajs
gneiss in Italian: Ortogneiss
gneiss in Luxembourgish: Gneis
gneiss in Lithuanian: Gneisas
gneiss in Hungarian: Gneisz
gneiss in Macedonian: Гнајс
gneiss in Dutch: Gneis
gneiss in Japanese: 片麻岩
gneiss in Norwegian: Gneis
gneiss in Norwegian Nynorsk: Gneis
gneiss in Polish: Gnejs
gneiss in Portuguese: Gnaisse
gneiss in Romanian: Gnais
gneiss in Russian: Гнейс
gneiss in Slovak: Rula
gneiss in Serbian: Гнајс
gneiss in Finnish: Gneissi
gneiss in Swedish: Gnejs
gneiss in Ukrainian: Гнейс
gneiss in Chinese: 片麻岩

Synonyms, Antonyms and Related Words

aa, abyssal rock, basalt, bedrock, block lava, brash, breccia, conglomerate, crag, druid stone, festooned pahoehoe, granite, igneous rock, lava, limestone, living rock, magma, mantlerock, metamorphic rock, monolith, pahoehoe, pillow lava, porphyry, pudding stone, regolith, rock, ropy lava, rubble, rubblestone, sandstone, sarsen, schist, scoria, scree, sedimentary rock, shelly pahoehoe, stone, talus, tufa, tuff
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