a coarsegrained metamorphic rock resembling granite, consisting of alternating layers of different minerals, such as feldspar, quartz, mica, and hornblende, and having a banded appearance
Origin of gneissGerman gneis from Old High German gneisto, a spark, akin to Old Norse gneisti, Old English gnast: from the luster of certain of the components
A banded or foliated metamorphic rock, usually of the same composition as granite.
Origin of gneissGerman Gneis probably alteration of Middle High German ganeist spark (from its appearance) from Old High German gneista
- gneiss′ic gneiss′oid′ gneiss′ose′
(usually uncountable, plural gneisses)