Hierarchy classification:

1. top of the aat hierarchies
2. Materials Facet
3. Materials (hierarchy name)
4. materials (substances)
5. [materials by form]
6. [materials by chemical form]
7. compounds (materials)

Anotations

Scope note:

Compound known as a hygroscopic, blue-gray powder that occurs naturally as the mineral "vivianite (mineral)." Used in the pigment "blue ocher"; has been found in Roman paint residues. Ferrous phosphate is also used as a colorant in ceramics.