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. sedimentary rock
9. [sedimentary rock by form]
10. rudaceous rock
11. breccia

Anotations

Scope note:

A striking breccia quarried in the Blue Ridge Mountains in Maryland and Virginia; it consists mostly of limestone, quartz pebbles, and multicolored fragments ranging from sand grains to cobbles, all cemented together in a calcareous matrix. It can be extremely difficult to work as the hard pebbles tend to break away from the softer matrix.