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. pyrobitumen

Narrower term/s

• anthracite
• bituminous coal
• cannel coal
• lignite[+]
  • jet (coal)

Anotations

Scope note:

Carbon-rich material that most often occurs in stratified sedimentary deposits. It is one of the most important of the primary fossil fuels. It is characterized by being solid, hard, opaque, black, or blackish, found in seams or strata in the earth, and largely used as fuel; it consists of carbonized vegetable matter deposited in former epochs of the world's history.