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. igneous rock
9. [igneous rock by origin]
10. extrusive rock
11. pyroclastic rock
12. volcanic glass

Narrower term/s

• tezontle

Anotations

Scope note:

A pale gray, porous variety of the volcanic stone rhyolite; it is composed of potassium aluminum silicate with small amounts of iron and alkalis. Pumice is used as an abrasive for polishing jewelry, cleaning metals, and smoothing vellum and parchment. In its solid form it is used as an abrasive and aggregate and in its powdered form it is used as a polish and abrasive.