Andersonita
Andersonita is a mineral with formula Na₂Ca(UO₂)(CO₃)₃·6H₂O, in the Carbonatos de uranilo group. This specimen comes from Mina Eureka, Castell-estaó, Lleida, Catalunya, España and joined the Terrium collection in 2025.
Description
A piece of grey sandstone with a black band of carbonaceous (organic) matter, "stained" by almost imperceptible pale-green crusts. To the naked eye it looks like a dirty stone, but that crust is andersonite: under UV light it shows a very strong neon-green fluorescence.
About Andersonita
Andersonite is a hydrated uranyl carbonate of sodium and calcium that forms small fluorescent crusts. At this locality it is a post-mining mineral: it has grown on the mine walls after the galleries were opened, the result of humidity and recent oxidation.
About the locality
The Eureka Mine is a small trial working in the Lleida Pyrenees, noted as the only place in Spain with a paragenesis of uranium–vanadium minerals associated with fossilised plant remains (logs) in Triassic sandstones.
Technical data
- Catalogue No.
- 0287
- Composition
- Na₂Ca(UO₂)(CO₃)₃·6H₂O
- Name
- Andersonita
- Group
- Carbonatos de uranilo
- Category
- Núcleus Ardens
- Matrix
- Arenisca
- Associations
- Materia carbonosa
- Mine
- Mina Eureka
- District / Municipality
- Castell-estaó
- Province
- Lleida
- Region
- Catalunya
- Country
- España
- Size (cm)
- 5.5 x 3.6 x 1.5
- Weight
- 21.7 g
- Acquired
- 2025
- Etymology
- Named in honour of Charles A. Anderson (1902–1990).
- Quality
- Buena
- Value trend
- Estable
Related specimens
- Abellaíta — España
- Abernathyita — España
- Abernathyita — España
- Abernathyita — España
- Aerenita — España
- Aerinita (fibrosa) — España
- Analcima — España
- Analcima — España