gneiss

• POS: Noun

CIDE DICTIONARY

gneiss, n. [G.].

 A crystalline rock, consisting, like granite, of quartz, feldspar, and mica, but having these materials, especially the mica, arranged in planes, so that it breaks rather easily into coarse slabs or flags. Hornblende sometimes takes the place of the mica, and it is then called hornblendic gneiss or syenitic gneiss. Similar varieties of related rocks are also called gneiss.  [1913 Webster]

OXFORD DICTIONARY

gneiss, n. a usu. coarse-grained metamorphic rock foliated by mineral layers, principally of feldspar, quartz, and ferromagnesian minerals.

Derivative

gneissic adj. gneissoid adj. gneissose adj.

Etymology

G

THESAURUS

gneiss

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