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. metamorphic rock
9. marble (rock)
10. [marble by form or function]
11. shell marble

Anotations

Scope note:

A group of shell marbles, the name deriving from 'lumaca,' the Italian word for snail. There are both ancient and modern varieties; the best known modern lumachella comes from Tirol in Austria and is dark gray-brown with shells retaining their pearly lining.