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. glass (material)
8. [glass by technique]
9. art glass (material)

Anotations

Scope note:

Term used in the glass trade for an opal glass which has been acid finished and had various ornate designs embedded in the glass in shades of brown and beige. A type of art glass, developed by the Mt. Washington Glass Company.