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

Narrower term/s

• ganister
• silcrete

Anotations

Scope note:

A metamorphic rock composed largely of granular quartz which is cemented by silica forming a homogeneous mass of very high tensile and crushing strengths; especially used as a building stone, as gravel in road construction, and as aggregate in concrete.