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. mineral

Anotations

Scope note:

A mineral composed of aluminum sulfate and hydrous basic calcium often formed by the reaction of sulfates and concrete or mortar. Ettringite crystal formation induces sulfate decay in the cement paste matrix. Conservation interventions seek to remove ettringite or limit its attack.