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

Narrower term/s

• tanzanite
• thulite

Anotations

Scope note:

A natural silicate of calcium and aluminum silicate, Ca2Al3(SiO4)3OH, characteristic of regional metamorphism and of hydrothermal alteration of igneous rocks. A member of the epidote group of nesosilicates, it is a lustrous transparent to translucent stone with color ranging grayish-white, peach, pink (thulite), blue (tanzanite) or green. Named for Baron Zois van Edelstein (1747-1819).