Hierarchy classification:

1. top of the aat hierarchies
2. Materials Facet
3. Materials (hierarchy name)
4. materials (substances)
5. [materials by origin]
6. biological material
7. animal material
8. [animal material by form or function]
9. [animal material by egg and egg components]
10. [egg components as materials]

Narrower term/s

• ostrich eggshell
• emu eggshell

Anotations

Scope note:

Material comprising or processed from the hard exterior covering of eggs, usually eggs of chickens or other birds. The thin, brittle shell from an egg is primarily composed of keratin and calcite. Eggshell may be decorated and valued intact or as a component of a cup or other object. Eggshell is also used as pigment and in grounds for silver point drawings. For preparation, the shells are washed, crushed and boiled in water with some quicklime. The sequence is repeated until the eggshells form a fine, white powder.