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]
9. sand

Anotations

Scope note:

Consists largely of glauconite, a greenish granular mineral containing up to 25% iron, with a large percentage of silica and some potash and aluminum, used especially as a water softener and as a source of potash.