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 property]

Anotations

Scope note:

Bluish white, fiery, opalescent, translucent glass that has been made white by the addition of calcium phosphate (bone ash) and opalescent by the addition of fluorides (fluorspar, cryolite, or lepidolite) and/or arsenic. Red tones appear in transmitted light. Opal glass was used for windows, bowls, light shades, table tops, and cosmetic jars.