BGS Rock Classification Scheme

Tonstein - A type of monomineralic aluminium-silicate sedimentary rock. It is a band of mudstone composed dominantly of kaolinite and associated with coal seams. British Geological Survey Research Report RR/99/03, section 13.6.

Code KRMST
Description Tonstein - A type of monomineralic aluminium-silicate sedimentary rock. It is a band of mudstone composed dominantly of kaolinite and associated with coal seams. British Geological Survey Research Report RR/99/03, section 13.6.
Qualifiers No qualifiers currently exist.
Definition Siliciclastic sedimentary rock with >50vol% clasts from pre-existing siliceous rocks. Particles >50% or predominantly mud-grade, <0.032mm. Hydrated aluminium silicate rich, >20% kaolinite, associated with coal seams. Synonym for tonstein.
Linked data http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/KRMST

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.