Gneiss (/ naɪs / nice) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. This rock is formed under pressures ranging from 2 to 15 kbar, sometimes even more, and temperatures over 300 °C (572 °F).

Apr 23, 2023 · Gneiss is a foliated metamorphic rock that is a common distribute type of rock high-grade regional metamorphic approaches from pre-current formations that have been initially both igneous or sedimentary rocks. It has a glorious banding which is apparent on microscopic scale and hand specimen.

Gneiss is a medium- to high-grade foliated metamorphic rock displaying a coarse-grained banding (also known as gneissose structure). ‘Gneiss’ derives, indeed from the German gneist, ‘spark’, likely a reference to the presence of large grains that reflect light.

Gneiss usually forms by regional metamorphism at convergent plate boundaries. It is a high-grade metamorphic rock in which mineral grains recrystallized under intense heat and pressure.

The meaning of GNEISS is a foliated metamorphic rock corresponding in composition to a feldspathic plutonic rock (such as granite).

Gneiss is a coarse-grained foliated metamorphic rock that displays alternating bands of light and dark minerals, formed from high-grade metamorphism. The light minerals are typically interlocking crystals of quartz and feldspar, while the dark bands are made of mafic minerals and often display a preferred orientation.

Gneiss is a widely distributed type of metamorphic rock. It is coarser than schist and has a distinct pattern of bands. Its mineral content is mainly feldspar. Quartz, micas (such as muscovite and biotite), and hornblende are also often present. The term gneissose is used to describe rocks with properties similar to gneiss.

gneiss, metamorphic rock that has a distinct banding, which is apparent in hand specimen or on a microscopic scale. Gneiss usually is distinguished from schist by its foliation and schistosity; gneiss displays a well-developed foliation and a poorly developed schistosity and cleavage.

Jun 8, 2018 · Gneiss (pronounced "nice") is a metamorphic rock consisting mostly of quartz and feldspar and showing distinct layering or banding. The layering of a gneiss may be weak or well-developed and consists of varying concentrations of biotite, garnet, hornblende, mica, and …

Dec 30, 2022 · Gneiss is a high-grade metamorphic rock known for its pronounced banding and layered appearance. This banding results from the high-temperature and high-pressure conditions under which it forms, where original rock minerals recrystallize and segregate into alternating light and dark layers.