Hierarchy classification:

1. top of the aat hierarchies
2. Materials Facet
3. Materials (hierarchy name)
4. materials (substances)
5. [materials by composition]
6. inorganic material
7. rock (inorganic material)
8. sedimentary rock
9. [sedimentary rock by form]

Narrower term/s

• septarium

Anotations

Scope note:

Rock characterized by, consisting of, or producing concretions; concretions are hard, compact aggregates of mineral matter, subspherical or irregular in shape, formed by precipitation from water solution around a nucleus, such as a shell or bone, in a sedimentary or pyroclastic rock. Concretions are generally different from the rock in which they occur, and represent a concentration of some minor constituent of that rock. Concretionary stones include flint, chert, and nodules of impure limestone which sometimes occur in clay.