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Gneiss - Wikipedia


Gneiss is a common distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks. It is often fol...

What type of rock has light and dark layers - Answers.com


foliated. ... What layer or layers of soil includes rock particles mixed with dark products of decay? topsoil .... What rock has parallel bands of dark and light mineral grains?

Rock Key


If there are a lot of pebbles mixed with the sand, it is called gravel. .... The rock has crystals, layers that look like ribbons or bands of minerals running through it, and is kind ... Is the rock mostly light or medium gray, not very dark gray or black?

Chapter 4 Rocks and Minerals - Volcano World


This layer of rock extends down to 40 miles from the surface of the earth. ... The lava has cooled and is now a volcanic rock called basalt. .... Some minerals sparkle in the light while others are dull and boring!! ... If the mineral shows a scratch mark from one of the testing materials the mineral is said to be less hard than the ...

Rock and Mineral identification Flashcards | Quizlet


Streak: colorless or light colored ... Scoria. Extrusive Igneous Rock Color: medium to dark. Streak: Layers: .... Other: sometimes has bands (stripes) of different colored minerals caused by the reorganization of minerals during metamorphosis.

Metamorphic Rocks


3- Foliation – The alignment of platy minerals or alternating layers of light (felsic) and dark ... has properties of both a gas and a liquid. Supercritical ... minerals align or alternating light and dark layers form, giving the rock a ... Distinguished based on composition, but may be foliated if subjected to ... form compositional b...

Metamorphic Rocks


The light and dark bands (gneissic banding) are alternations of felsic vs. mafic layers. Slate is a product of low grade metamorphism (not terribly great burial ...

definitions - Math/Science Nucleus


Anthracite, A very hard, black coal; has the highest carbon content and heating value; ... Banded, Alternating bands of light and dark-colored minerals ... Bed, One of several parallel layers of rock arranged one on top of another; one of a ..... Roundness, Angularity/roundness refers to whether the grains are smooth or jagged ...

Geology Word of the Week: M is for Migmatite - Georneys - AGU ...


Aug 28, 2011 ... Migmatites are hybrid rocks: the dark layers (most often composed of biotite ... If a gneiss experiences just slightly higher temperatures, it may partially melt and become a migmatite. ... This theory has now been largely abandoned, and geologists now ... Fine bands of light and dark minerals in migmatite.

Metamorphic Rocks


Metamorphic rocks are consequently rocks that have undergone a change or ... results in light and dark colored minerals being concentrated in alternating layers . ... If these mica minerals grow during deformation, they will be aligned with their ... Each of these minerals has the same chemical composition (Al2 SiO5 ), but ...

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Metamorphic Rock Classification - faculty at Chemeketa


Foliation refers to flat or wavy planar features (looking like layers) caused by the ... Foliation may also look like alternating bands of light and dark minerals. In contrast, a nonfoliated rock has interlocking grains with no specific pattern. Foliated ...

Igneous Rocks


The word "texture" has nothing to do with how the rock feels. ... Geologists look at the proportions of light-colored and dark-colored minerals in an igneous rock to estimate the ... Each layer of sedimentary rock is like a chapter in the history of the earth. .... If these stresses do melt the original rock, an igneous rock i...

Foliated Metamorphic Rocks | Mineralogy4Kids


Foliated metamorphic rocks are formed within the Earth's interior under extremely ... crystals are larger with the grains aligned in parallel to subparallel layers ... and pressures; coarse grained texture of alternating light and dark mineral bands .