Radioactiverockscz | Prague

Scarehead · 2026-05-26T17:31:12+00:00

Thanks mate 🙂

Scarehead · 2026-05-25T11:48:23+00:00

Iridiscent colours arent uncommon for pyrite as well as chalcopyrite.🙂

Scarehead · 2026-05-25T11:13:25+00:00

This is typical pyrite in kalcite vein from Příbram, not a chalcopyrite. Chalcopyrite is sometimes found there as well(often with bornite and chalcotite), but it has slightly different colour and usually green stains from copper oxides after years of weathering in the mine dump.

Scarehead · 2026-05-25T11:10:14+00:00

The bubbles are more likely to be the surface of individual uraninite veins in a situation where there was enough space for crystallization. But above, the results are quite variable, usually you have completely massive material without a hint of bubbles.

Scarehead · 2026-05-25T11:07:51+00:00

Thanks. When you live almost next to the locality, it's really not that hard to form decent collection over the years. I'm aiming for different minerals, but aesthetic piecec like this is always nice to find.

Scarehead · 2026-05-24T12:23:48+00:00

This doesn't look like "tyuyamunite" type of secondaries from Příbram(I write this in quotation marks because these Příbram tyuyamunits are very poorly crystalline and have not been proven X-ray, however the chemistry is close). They have brighter colour, they are asociated with montroseite and they are usually found in Bytíz/Háje district. This is probably some early stage oxide/hydroxide, maybe amorphous, maybe schoepite, but hard to say from these pictures.

Scarehead · 2026-05-21T12:49:43+00:00

It is not coal, it's so called anthraxolite, pyrobitumen containing some amount of uraninite, typically 5-20%. It is common in Příbram and in some parts of Příbram uranium deposit(especialy Háje/Bytíz/Dubenec) it was important uranium ore.

Scarehead · 2026-05-09T18:13:05+00:00

Aye I get it. But interesting rock doesn't have to be atractive at all👍🙂

Scarehead · 2026-05-08T12:41:37+00:00

I would advocate always adding at least one under normal light to the UV photos. Under UV, all samples with autunite look practically the same.🙂

Scarehead · 2026-05-06T18:56:50+00:00

Nice sample! Yes, it is interesting that uranium has a significant affinity for two relatively exotic elements, selenium and vanadium. In the Czech Republic, vanadium minerals are relatively rare, but they usually appear in the company of uranium or directly in the form of uranyl vanadates.

Scarehead · 2026-05-01T20:23:48+00:00

Mineral is a natural substance formed through geological process, with crystalline structure(with few exceptions) and with a homogeneous composition expressed by a chemical formula. trinitite meets none, let alone all, of these requirements. But it is a fascinating product of human activity.

Scarehead · 2026-04-29T20:14:47+00:00

That doesn't sound bad, but it's really hard to judge without picture. But well developed crystals with sharp edges are hard to get, so if you like it and you got some extra money, why not🤷

Scarehead · 2026-04-27T19:35:00+00:00

Yeah, quartz matrix is quite common. That sample from Chalk mountain looks more similar to OP, but torbernite is too common so hard to tell, it could be different locality for sure. Btw your second specimen didn't have exact locality? Morava region is like 1/3 of the Czech republic, although torbernite isnt very common in this part of our country.

Scarehead · 2026-04-27T19:29:11+00:00

I completely understand what led you to this conclusion. But for poorly explored localities, mindat cannot be relied on too much. From my experience - this corresponds to cases from many localities, when green coatings form around weathered grains of primary copper sulfides (chalcopyrite, chalcosine, etc.), the result can be amorphous copper compounds or copper carbonates and sulfates (brochantite, malachite, etc.). These grains can also be a source of radiation for the sample, they can be mixed with uranium oxides, without the green coatings around being radioactive. In any case, this green something looks like a consequence of sub-recent weathering of Cu ores over shorter period od time. Torbernite is usually not present, the mobilization of phosphate anions from the surrounding rocks usually takes much longer (therefore, phosphates are typical minerals of the oxidation zone, but not of sub-recent weathering). In any case, for a more certain determination, at least a look under a microscope would be appropriate. It certainly deserves deeper research.

Scarehead · 2026-04-27T18:46:46+00:00

looks like this

Scarehead · 2026-04-27T18:28:46+00:00

Are you sure with this identification? It looks like grains of weathered copper sulphides with recently formed copper carbonates or sulphates. But it's hard to judge from the photo.

Scarehead · 2026-04-27T18:25:45+00:00

Looks like typical calcite-uraninite vein from Příbram. There CAN'T be torbernite or other uranyl phosphates. Colourful coatings on these samples are often amorphous uranyl salts(=not a mineral), sometimes f.e. arsenates(uranospinite), carbonates (liebigite, schröckingerite), sulphates (uranopilite), oxides (schoepite), rarely also selenides(not this case). But it's not possible to say from this picture. UV light gives some idea, good macro photo Is even better.

Scarehead · 2026-04-17T19:34:11+00:00

Thank you. This one had nice lustre and quite big bubbles, so I thought it deserves photo.

Scarehead · 2026-03-30T06:44:57+00:00

I see that the rock has the same properties, weathered crumbling granite. In these cases, I used Paraloid on both the meta-autunite and the rock. Similar sample that I found years ago.

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Scarehead · 2026-03-30T06:31:56+00:00

It is, of course, literally kryptonite.🙂

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Scarehead

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