Hierarchy classification:

1. top of the aat hierarchies
2. Materials Facet
3. Materials (hierarchy name)
4. materials (substances)
5. [materials by composition]
6. organic material
7. bituminous material
8. natural bituminous material
9. bitumen (material)
10. asphalt (bituminous material)

Anotations

Scope note:

Asphalt found in natural deposits, as distinguished from asphalt formed as a residue from the distillation of petroleum. Natural asphalt is found where crude oil seeps from the ground. It was formed during an early stage in the breakdown of organic marine deposits into petroleum. It characteristically contains minerals, while residual petroleum asphalt does not (although minerals may be added).