Hierarchy classification:

1. top of the aat hierarchies
2. Materials Facet
3. Materials (hierarchy name)
4. materials (substances)
5. [materials by composition]
6. combination inorganic/organic material
7. soil
8. [soil by composition or origin]

Anotations

Scope note:

A residual product of rock decay that is red in color and has a high content in the oxides of iron and hydroxide of aluminum and a low proportion of silica. Used in African and Asian building construction.