Schists
"Schists are regional
metamorphic rocks."
They are formed in low to medium pressures and temperatures.
They are foliated rocks, with a layered fabric which consists of thin planes that are easily broken off.
They often have a layering of light and dark minerals.
The grain size is medium, with visible mineral crystals.
The major minerals are quartz, feldspar and some platy mica minerals such as biotite and muscovite.
Other platy ones include graphite, talc and chlorite.
Minor minerals are kyanite, hornblende, actinolite and garnet.
Those vary between different types such as kyanite, garnet, green-, or blueschist.
The mineral composition depends on the exact metamorphic conditions in which it formed and the original rock from which it formed.
By njwilson23
Back to Types of Metamorphic Rocks
More about Metamorphic Rocks
