Vivianita
Vivianita is a mineral with formula Fe²⁺₃(PO₄)₂·8H₂O, in the Fosfatos group. This specimen comes from Mina Siglo Veinte, Llallagua, Rafael Bustillo, Potosí, Bolivia and joined the Terrium collection in 2025.
Description
Single elongate square prism, gem quality, very dark green, with several bluish reflections on one face; transparent in transmitted light, with inclusions producing phantoms and longitudinal parallel growth.
About Vivianita
Hydrated iron phosphate considered a "necromineral" for its origin in the interaction between organic phosphates and iron—i.e., from post-mortem organic remains. Photosensitive: it darkens over time as it oxidises, shifting from blue to green.
About the locality
Historic tin-mining district that in 1967 was the scene of the largest workers' massacre in the country, and twenty years later would be closed under IMF imposition, ending state operation. Today it is worked by self-managed cooperatives, and these vivianites are increasingly difficult to find.
Technical data
- Catalogue No.
- 0313
- Composition
- Fe²⁺₃(PO₄)₂·8H₂O
- Name
- Vivianita
- Group
- Fosfatos
- Category
- Estélites
- Mine
- Mina Siglo Veinte
- District / Municipality
- Llallagua
- Province
- Rafael Bustillo
- Region
- Potosí
- Country
- Bolivia
- Size (cm)
- 6.5 x 0.7 x 0.7
- Acquired
- 2025
- Etymology
- In honour of John Henry Vivian (1785–1855), British mineralogist and politician who discovered it in 1817.
- Quality
- Buena
- Value trend
- Estable