What is the protolith of schist?

Schist is a crystalline metamorphic rock, mostly composed of more than 50% tabular and elongated minerals with grainsize coarse enough to be visible to the unaided eye. The protolith of schists can be igneous (e.g. basalt, volcanic tuff) or sedimentary (clay, mud).

What is the grain size of mica schist?

The mineral grains in a schist are typically from 0.25 to 2 millimeters (0.01 to 0.08 in) in size and so are easily seen with a 10× hand lens. Typically, over half the mineral grains in a schist show a preferred orientation.

What is the parent rock of muscovite schist?

Mica Schist

What does muscovite schist look like?

Muscovite schist: The dominant visible mineral in this schist is muscovite. Its platy grains are aligned in a common orientation, and that allows the rock to be split easily in the direction of the grain orientation. The specimen shown is about two inches (five centimeters) across.

What is schist mainly composed of?

Most schists are composed largely of platy minerals such as muscovite, chlorite, talc, sericite, biotite, and graphite; feldspar and quartz are much less abundant in schist than in gneiss.

How hard is mica schist?

Hardness – generally hard. Colour – variable – often alternating lighter and darker bands, often shiny. Mineralogy – mica minerals ( biotite, chlorite, muscovite), quartz and plagioclase often present as monomineralic bands, garnet porphyroblasts common. Other features – generally smoothish to touch.

Why is Mica shiny?

Mica minerals! They sparkle because light is reflected on their flat surfaces, which are where the mineral breaks along its plane of cleavage. These minerals break so easily along their cleavage that some crystals have broken into many thin layers that look like the pages of a little book.

What is the color of schist?

Schist is darker in color than gneiss. In color photographs or with the naked eyes, schist appears gray. In Figure 4.8, note that the overall reflectance of schist is lower than 50% that of the MgO standard. Schist has an abundance of phyllosilicate minerals, so schistosity and foliation are pronounced.

Is Mica rock worth anything?

The most important sources of sheet mica are pegmatite deposits. Sheet mica prices vary with grade and can range from less than $1 per kilogram for low-quality mica to more than $2,000 per kilogram for the highest quality.

Are schist rocks worth anything?

Schist may be worth mining if it contains useful minerals in large concentration. Common minerals extracted from schistose metamorphic rocks are garnet, kyanite, talc and graphite. A heap of quartz schist slabs demonstrating platy habit which is caused by the abundance of platy minerals.

What kind of rock is the protolith of schist?

The protolith of schists can be igneous (e.g. basalt, volcanic tuff) or sedimentary (clay, mud). Click to see full answer. Similarly, you may ask, what is the parent rock of schist? Schist is a coarse grained metamorphic rock.

What kind of minerals are in muscovite schist?

green, grey, dark brown (Biotite schist), silver (Muscovite schist), also other colours depending on the schist-type. Main minerals: quartz, mica (muscovite, chlorite, biotite), feldspar, talc, graphite, hornblende, garnet.

Which is the parent rock of mica 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 are the names of the different types of schist?

There are many varieties of schist and they are named for the dominant mineral comprising the rock, e.g. mica schist, green schist (green because of high chlorite content), garnet schist, actinolite schist, biotite schist etc.