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. mineral

Anotations

Scope note:

A yellow or brown-colored siliceous alteration product resulting from the hydration of basaltic volcanic glass that has undergone rapid chilling. It is found as pyroclastic cones in areas where basaltic eruptions come in contact with water, as in the Galapagos Islands.