Uraninita Pechblenda
Uraninita is a mineral with formula UO₂, in the Óxidos group. This specimen comes from Alto Palatinado, Oberpfalz, Bayern (Bayern), Alemania and joined the Terrium collection in 2025.
Description
Black uraninite crest with the characteristic greasy or pitchy lustre that gives the variety "pechblende" its name, on reddish-brown matrix. Heavy for its size (42 g) and very representative of German uranium. Emission of 23.3 µSv/h.
History of this specimen
In nature, uranium occurs almost entirely as its isotope U-238; U-235 represents only a very small fraction, and U-234 remains in traces. However, that scarce U-235 is the fissile isotope: on capturing a neutron, its nucleus becomes unstable and can split into two lighter fragments, releasing energy and several more neutrons. Those neutrons can trigger new fissions, giving rise to a chain reaction. Hence uranium enrichment consists of increasing the proportion of U-235. To do this, the uranium is converted into uranium hexafluoride and centrifuged in the gas phase, progressively raising the concentration. As nuclear fuel, enrichments of 3–5% usually suffice; above 20% it is considered highly enriched uranium, and around 90% or more is weapons grade. This piece is very old; in my collection it came in its little cardboard box, but at some point in its life it lost its label and, with it, its provenance.
About Uraninita
Uraninite has a past of secrets and revolutions. When it was still called pechblende, in 1789—while the Bastille was being taken in France—Klaproth discovered uranium in it. A century later, the Curies hand-processed eight tonnes of this rock to isolate polonium and radium, revealing something new that would change the world: it contained radioactivity. The old name "pechblende" preserves Central European miners' contempt for a mineral that deceived them. "Pech" refers to pitch—for its black, greasy appearance—but also to bad luck; "blende" derives from the German verb "blenden", to deceive. As with sphalerite, miners applied that name to a material that seemed to promise useful ore and yielded neither lead nor silver. Mineralogy ended up fixing as a historical term an old miners' insult. They hated it.
About the locality
The Upper Palatinate hosts hydrothermal deposits set in Hercynian granites, where uranium typically occurs as nodules or compact masses like this.
Technical data
- Catalogue No.
- 0235
- Composition
- UO₂
- Name
- Uraninita
- Variety
- Pechblenda
- Group
- Óxidos
- Category
- Núcleus Ardens
- Matrix
- Matriz granítica
- Associations
- Productos de alteración (Gummita)
- Mine
- Alto Palatinado
- Province
- Oberpfalz
- Region
- Bayern (Bayern)
- Country
- Alemania
- Size (cm)
- 4.5 x 3 x 2
- Weight
- 42.2 g
- Acquired
- 2025
- Etymology
- Uraninite was formerly known as pechblende, as sphalerite was once called blende. Both historical names are fossilised insults. Medieval Saxon miners combined two pejorative terms: "Pech" (pitch, but also "bad luck") and "blenden" (to deceive). Both were "blendes" because they misled generations of miners—one promised lead and the other silver—and neither delivered. Mineralogy has preserved the miners' insult in the official name.
- Quality
- Buena
- Value trend
- Al alza
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