What is the original rock of schist?
What is the original rock of schist?
The original parent rock (or protolith) of mica schist is shale. Phyllite could also be considered the parent rock as mica schist is a more highly metamorphosed phyllite.
What is the original parent rock of schist?
∎ Schists are primarily composed of silicate minerals such as mica (muscovite and biotite), quartz, and feldspar . ∎ Shale, siltstone, and some sandstones can provide the parent rock for schist.
What minerals are in biotite schist?
For example, a quartz-feldspar-biotite schist is a schist of uncertain protolith that contains biotite mica, feldspar, and quartz in order of apparent decreasing abundance.
What type of rock is biotite schist?
metamorphic rock
Schist is a type of metamorphic rock in which lamellar minerals, such as muscovite, biotite, and chlorite, or prismatic minerals, such as hornblende and tremolite, are oriented parallel to a secondary platy or laminated structure termed the schistosity.
What is the texture of biotite schist?
Texture – foliated, foliation on mm to cm scale. Grain size – fine to medium grained; can often see crystals with the naked eye. Hardness – generally hard. Colour – variable – often alternating lighter and darker bands, often shiny.
What is the Protolith for a schist rock?
The protolith of schists can be igneous (e.g. basalt, volcanic tuff) or sedimentary (clay, mud).
What is biotite made of?
Biotite is regarded as a mixture composed of variable proportions of four basic aluminosilicates of potassium, iron, magnesium, or aluminum: annite, K2Fe6(Si6Al2O20)(OH)4; siderophyllite, K2Fe5Al(Si5Al3O20)(OH)4; phlogopite, K2Mg6(Si6Al2O20)(OH)4; and eastonite, K2Mg5A1(Si5Al3O20)(OH)4.
Is biotite valuable?
Biotite is a common rock forming mineral, being present in at least some percentage in most igneous and both regional and contact metamorphic rocks. Biotite is rarely considered a valuable mineral specimen, but it can accompany other minerals and compliment them.
What are the common characteristics of schist which differentiates it from slate phyllite and gneiss?
Gneiss tends to be more coarse-grained than schist, with light and dark (‘felsic’ and ‘mafic’) mineral layers known as gneissic banding. These layers are much thicker and more irregular than any found in schists, thus a more distinct foliation is observed.
What is the colour of biotite schist?
3. What is the colour of biotite schist? Explanation: Since the biotite is metamorphosed to form biotite-schist, the colour is not changed much and hence the colour of biotite-schist is also black.
What kind of rock is andesite?
igneous rock
Andesite most commonly denotes fine-grained, usually porphyritic rocks; in composition these correspond roughly to the intrusive igneous rock diorite and consist essentially of andesine (a plagioclase feldspar) and one or more ferromagnesian minerals, such as pyroxene or biotite.
