Metamorphic rocks - Schist

Page / - last modified by Roelof Zwaan on 2021/09/30 15:18

Schist

last modified by Roelof Zwaan

on 2021/09/30 15:18

Table of Contents

Schist is a foliated metamorphic rock made up from plate-shaped mineral grains. This rock originates from shale and transformed from shale into slate, then phyllite and finally into schist. If the rock is transformed any further it becomes a gneiss.

Characteristics

Schist originate from regional metamorphism at the continental side of a convergent plate boundaries, which mean it forms under moderate pressure and moderate temperature conditions. A schist can be defined on its behaviour. When it breaks it produces thin flakes of clay minerals that also can be seen by the naked eye. A schist can't be defined on its mineral composition, but only on the fact of enough platy metamorphic minerals present.

Composition

Schist mainly consist of mica minerals such as chlorite, muscovite and biotite. These exist in the rock because they are deformed clay minerals. Moreover are quartz and feldspars present in this type of metamorphic rock. A schist can also be named according to the abundant minerals when the rock is examined. For example a chlorite schist, graphite schist or garnet schist. These extra names need to be a mineral with metamorphic origin.

References

NEN-EN-ISO 14688-1:2019

https://geology.com/

Schist

Type	Metamorphic rock
Texture	Platy
Clasts	Can be present
Hardness	Hard
Color	Mainly grey
Minerals	Quartz or feldspar and mica minerals
Touch	Smooth
Image	Schist

Contents

Characteristics

Composition

References

Schist