Uraninita
Uraninita is a mineral with formula UO₂, in the Óxidos group. This specimen comes from Mina Eureka, Castell-estaó, Lleida, Catalunya, España.
Description
Compact mass of black microgranular uraninite with dark metallic reflections and small green coatings attributable to roscoelite and possibly billietite. Sandy greyish-brown matrix with irregular fracture and earthy texture. Shows an emission of 16.5 µSv/h measured at the surface.
History of this specimen
Henri Becquerel discovered spontaneous radioactivity in 1896. Marie Skłodowska and Pierre Curie extended the study of the phenomenon and in 1898 announced polonium and radium; in 1903 the three shared the Nobel Prize in Physics for their research into radioactivity. Because the Curies worked with pitchblende, massive uraninite from Joachimsthal, now Jáchymov, they were not dealing with simple UO₂, but with a natural mineral containing uranium, impurities and decay products accumulated over millions of years. They found that, after the uranium salts used by industry to colour glass and porcelain had been extracted, the remaining slag continued to emit radiation. This anomalous radioactivity led them in 1898 to polonium and, shortly afterwards, to radium, both present in minute quantities in pitchblende as decay products of uranium. To demonstrate this they needed tonnes of residue from Joachimsthal: first they received a free consignment of 100 kg from the Austrian government, then imported several tonnes of material that industry regarded as waste.
About Uraninita
Uraninite (pitchblende) is the primary uranium mineral (UO₂). Black, metallic, and the source from which most secondary species derive (autunite, torbernite, uranophane, etc.). One of the most important sources of uranium and radium.
About the locality
The Eureka deposit, in the Vall Fosca, was one of the main Spanish uranium prospecting sites during the 20th century. Its veins show associations with torbernite, uranophane, roscoelite and betafite. Uraninite from Eureka can no longer be obtained in the field; it appears only in old collections from the area.
Technical data
- Catalogue No.
- 0214
- Composition
- UO₂
- Name
- Uraninita
- Group
- Óxidos
- Category
- Núcleus Ardens
- Associations
- roscoelita billietita (posible)
- Mine
- Mina Eureka
- District / Municipality
- Castell-estaó
- Province
- Lleida
- Region
- Catalunya
- Country
- España
- Size (cm)
- 6.5 x 4 x 2.3
- Weight
- 53.4 g
- Ex-collection
- Francisco Becerra
- Etymology
- From the element uranium, so named in 1789 by the chemist M. H. Klaproth in honour of the planet Uranus, which had been discovered only eight years earlier by William Herschel.
- Quality
- Muy buena
- Value trend
- Estable
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