Uraninita
Uraninita is a mineral with formula UO₂, in the Óxidos group. This specimen comes from Mina Eureka, Castell-estaó, Lleida, Catalunya, España and joined the Terrium collection in 2025.
Description
Dark uraninite vein in grey sandstone. Dull, microgranular aspect, with slight green-olive patinas. The piece registers a significant dose rate, around 30 µSv/h, indicating a high concentration of primary mineral.
History of this specimen
I bought it from Abella the same week I got an abellaite from Persson (Rare Minerals).
About Uraninita
Uraninite is the main ore of uranium. The variety "pechblende" (from German "Pech", pitch) is massive, botryoidal and opaque. It is highly radioactive and at Eureka it commonly appears altered, giving rise to rare species, because in reality pechblende is a material that for the most part consists of uraninite (UO₂), yes, but is in continuous internal (r)evolution: within a single grain coexist uranium, decay products such as radium and lead, structural damage from metamictisation (progressive disordering of the crystal lattice caused by the uranium's own radiation), and incipient secondary phases. It is not a clean block like quartz (SiO₂), but a mixture that records its own degradation over time.
About the locality
At Eureka uranium occurs filling fractures in Triassic sandstones (Buntsandstein). Although it is called a mine, it is in fact 1960s prospecting workings known as the "Eureka permit". It is a mineralogical haven: 60 species have been described, 26 of them uranium-bearing, and it is the type locality for abellaite and cejkaite. The crystals are not large, but the geochemical complexity is of the first order worldwide.
Technical data
- Catalogue No.
- 0203
- Composition
- UO₂
- Name
- Uraninita
- Group
- Óxidos
- Category
- Núcleus Ardens
- Matrix
- Arenisca
- Mine
- Mina Eureka
- District / Municipality
- Castell-estaó
- Province
- Lleida
- Region
- Catalunya
- Country
- España
- Size (cm)
- 5 x 1.7 x 1.5
- Acquired
- 2025
- Ex-collection
- Joan Abella
- Etymology
- From the element uranium, so named in 1789 by the chemist M. H. Klaproth in honour of the planet Uranus, discovered only eight years earlier by William Herschel.
- Quality
- Buena
- Value trend
- Estable
Related specimens
- Abellaíta — España
- Abernathyita — España
- Abernathyita — España
- Abernathyita — España
- Aerenita — España
- Aerinita (fibrosa) — España
- Analcima — España
- Analcima — España