BGS Earth Material Classes (concepts) is a classification of all types of earth material or other substance that may be recorded in a geological log or section (BGS Rock Classification Scheme RCSv3). These concepts are published as linked data.
IRI ~ http://data.bgs.ac.uk/ref/EarthMaterialClass/RockClassAll
Currently should resolve to: https://vocab.bgs.ac.uk/v/vocab/rthmtrlclss:RockClassAll
Data available for download through: https://github.com/BritishGeologicalSurvey/vocabularies/tree/main/vocabularies/EarthMaterialClass