Description
Schist is medium grade metamorphic rock, formed by the imetamorphosis of mudstone / shale, or some types of igneous rock, to a higher degree than slate, i.e. it has been subjected to higher temperatures and pressures. The resulting foliation is coarser and more distinct than that of slate due to the higher degree of crystallisation of mica minerals (biotite, chlorite, muscovite) forming larger erystals, and is often referred to as schistosity. These larger crystals reflect light so that schist often has a high lustre, i.e. it is shiny. Due to the more extreme formation conditions, schist often shows complex folding patterns. 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.
Uses
Although a very attractive stone, schist is rarely used as a building material as it is not very strong. Uses - generally used as a decorative rock in gardens.
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