noun
- a fine-grained sedimentary rock composed primarily of clay minerals, formed from the compaction and cementation of clay deposits.
Usage: geology; also called mudstone in some contexts
Examples
- The geologist identified layers of claystone in the rock formation.
- Claystone is commonly found in ancient lake beds and river deltas.
- The claystone deposits in this region are rich in fossils.
- Drilling through the claystone revealed the underlying sandstone layer.
- Claystone has low permeability, making it useful as a seal in oil reservoirs.