A metamorphic rock, commonly rich in quartz and feldspar, with a banded and foliated texture, formed at temperatures above about 550 degrees Centigrade
Coarse-grained metamorphic rock with discontinuous foliation caused by planar alignment of platy and lath-shaped minerals
formed at even higher temperatures than schists The grain size is larger than schist with banding and light coloured minerals
A coarse-grained metamorphic rock, composed of alternating light and dark bands, formed at very high temperatures and pressures
When a clay is metamorphosed under extreme conditions of heat and pressure a very small percentage of the rock may start to melt and this helps the new minerals forming in these conditions to segregate into bands A typical gneiss may at first glance resemble a granite, but the minerals form distinct dark and light folded and swirling bands Gneiss is typical of the ancient hearts of continents, and is found in Britain mainly in the extreme north-west of Scotland and on the Outer Hebrides The 'Lewisian Gneiss' of this area is by far the oldest rock in Britain
Medium-to coarse-grained metamorphic rock with parallel, somewhat irregular banding that has little tendency to split along planes. Gneiss is the principal rock over extensive metamorphic terrains. Orthogneiss is formed by the metamorphism of igneous rocks; paragneiss results from the metamorphism of original sedimentary rocks. Pencil gneiss contains rod-shaped individual minerals or segregations of minerals, and augen gneiss contains large lenticular mineral grains or mineral aggregates having the appearance of eyes scattered through the rock
A hard, coarse-grained, foliated (banded), metamorphic rock (altered by great temperature and/or pressure) of quartz, feldspar and mica; often has low water yield
A type of metamorphic rock formed as older rocks recrystallize under heat and stress from pressure characterized by a layering of light and dark bands or streaks
A metamorphic rock this may have been granite More info - http: //volcano und nodak edu/vwdocs/vwlessons/lessons/Slideshow/Merocks/Merock5 html
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
a coarse, foliated metamorphic rock in which bands of granular minerals (commonly quartz and feldspars) alternate with bands of flaky or elongate minerals (e g , micas, pyroxenes) Generally less than 50% of the minerals are aligned in a parallel orientation
A foliated rock formed by regional metamorphism, in which bands or lenticles of granular minerals alternate with bands or lenticles of flaky or elongate minerals
A foliated metamorphic rock corresponding in composition to granite or some other feldspathic plutonic rock It is medium- to coarse-grained and consists of alternating streaks or bands
A metamorphosed coarse grained igneous rock In this rock you get the recrystallization of quartz, feldspars, micas and amphiboles into bands
A coarse-grained, foliated metamorphic rock marked by bands of light-colored minerals such as quartz and feldspar that alternate with bands of dark-colored minerals This alternation develops through metamorphic differentiation
a banded or foliated metamorphic rock, usually of the same composition as a granite - BACK>>