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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 is a type of metamorphic rock that has parallel layers? Foliated rock has parallel layers. .... 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?

PA DCNR - Geology - Rock Types


Pennsylvania has had a variety of igneous rocks; however, most of these have undergone metamorphism. On the maps, they are classified simply as dark or light-colored. ... rock names are based on grain size, organization of minerals into layers ... Includes dark-colored gneiss and diabase (and kimberlite, if it is shown on ...

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 ...

Igneous Rocks


Both magma and lava cool and harden to form igneous rocks. ... The word " texture" has nothing to do with how the rock feels. ... Depending on the proportion of light minerals to dark minerals, igneous rocks can be broken into four main types: felsic, ... Each layer of sedimentary rock is like a chapter in the history of the e...

Rock and Mineral identification Flashcards | Quizlet


(dark rocks) Extrusive Igneous Rock Color: black or dark. Streak: Layers: ... Color: always going to be grey (light or dark) ... Other: sometimes has bands (stripes) of different colored minerals caused by the reorganization of minerals during ...

Metamorphic Rocks


James Hutton, a Scottish doctor became fascinated by metamorphic rocks and published .... 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 bands.

How do we Identify Metamorphic Rocks? — Mr. Mulroy's Earth Science


If the newly formed metamorphic rock has its minerals arranged in parallel layers, and the parallel layers form alternating bands of light then dark minerals it has ...

Rocks of Idaho


Very light-colored rocks are generally lacking in iron-bearing minerals. ... An abundance of these minerals will yield a gray to dark gray mineral. ... An important principle of geology holds that sedimentary rocks are deposited in horizontal layers. ... Extrusive rock has a very high component of glass because it was quickly ...

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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 ...

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 ...

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 ...