BGS Rock Classification Scheme
Schist - A type of metamorphic rock with unknown protolith based on textural attributes. In the Rock Classification Scheme, it is defined as a medium-grained strongly foliated rock that can be readily split into flakes or slabs due to the well-developed preferred orientation of the majority of the minerals present, particularly those of platy or prismatic habit. Schists occur characteristically in areas of medium-grade metamorphism and can encompass a wide range of lithologies. Note that orthoschist indicates a rock that is thought to have an igneous protolith, and paraschist indicates a rock that is thought to have a sedimentary protolith. British Geological Survey Research Report RR/99/02, sections 3.3, 6.1 and fig. 1.
| Code | SCH |
|---|---|
| Description | Schist - A type of metamorphic rock with unknown protolith based on textural attributes. In the Rock Classification Scheme, it is defined as a medium-grained strongly foliated rock that can be readily split into flakes or slabs due to the well-developed preferred orientation of the majority of the minerals present, particularly those of platy or prismatic habit. Schists occur characteristically in areas of medium-grade metamorphism and can encompass a wide range of lithologies. Note that orthoschist indicates a rock that is thought to have an igneous protolith, and paraschist indicates a rock that is thought to have a sedimentary protolith. British Geological Survey Research Report RR/99/02, sections 3.3, 6.1 and fig. 1. |
| Qualifiers | No qualifiers currently exist. |
| Definition | Medium-grained (av. 0.25-2mm) strongly foliated metamorphic rock; (protolith undefined) splits into <5mm slabs/flakes defined by well-developed planar orientation of platy/prismatic minerals |
| Linked data | http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/SCH |
CAVEAT
"Thumbnail" definitions attached to some of the table entries are an interim attempt to provide simple short descriptions of the "unqualified" rock types presented within the BGS Rock Classification Scheme. Every effort has been made to ensure accuracy and consistency but minor contradictions or omissions might be present. The BGS welcomes any feedback pointing out such minor imperfections and/or providing constructive comment and suggestions for improvement of the definitions. In the first instance such feedback should be directed to Dr Tim McCormick.