Table of Contents
What classification is gneiss?
metamorphic rock
Gneiss: a metamorphic rock displaying gneissose structure. Gneisses are typically layered (also called banded), generally with alternating felsic and darker mineral layers. Gneisses may also be lineated, but must also show segregations of felsic-mineral-rich and dark-mineral-rich concentrations.
What type of metamorphic rock is gneiss?
Gneiss is a high grade metamorphic rock, meaning that it has been subjected to higher temperatures and pressures than schist. It is formed by the metamorphosis of granite, or sedimentary rock.
Is gneiss a sedimentary metamorphic or igneous rock?
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.
What type of igneous rock is gneiss?
Gneiss is a coarse to medium grained banded metamorphic rock formed from igneous or sedimentary rocks during regional metamorphism. Rich in feldspars and quartz, gneisses also contain mica minerals and aluminous or ferromagnesian silicates.
Is gneiss regional or contact?
Most foliated metamorphic rocks—slate, phyllite, schist, and gneiss—are formed during regional metamorphism. As the rocks become heated at depth in the Earth during regional metamorphism they become ductile, which means they are relatively soft even though they are still solid.
Is gneiss intrusive or extrusive?
Many gneisses are made of the same minerals as coarse-grained intrusive rocks such as granite or diorite. This barn wall shows three large gneisses (black and white/pink striped rocks) plus several coarse-grained intrusive rocks.
Is anthracite regional or contact?
| Summary Chart of Common Metamorphic Rocks | ||
|---|---|---|
| Original Rocks | Metamorphic Equivalent | Metamorphism |
| granite | gneiss | regional |
| basalt | schist | regional |
| bituminous coal | anthracite coal | regional |
Is andesite a igneous rock?
Andesite is a fine-grained, extrusive igneous or volcanic rock. It is dark grey and made up of equal amounts of light and dark minerals, although the crystals are too small to be seen without a magnifier. Occasionally andesite may contain some larger crystals. Or small round pockets that were gas bubbles.