BGS Rock Classification Scheme

Mudstone, friable, calcareous

Code FCMST
Description Mudstone, friable, calcareous
Qualifiers friable   calcareous   
Definition Siliciclastic sedimentary rock that crumbles or abrades easily. Particles, >50% or predominantly mud-grade, <0.032mm. 5-20% unspecified primary carbonate.
Linked data http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/FCMST

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.