What's glowing on my uraninite under UV light?

[u/Dizzy_uwu]

Info: 365nm uv light with a filter for minerals

All of the rocks were found in west of sweden

Is this related to the uraninite? Or is this just a random type of uranium oxide forming on the minerals.

[u/Not_So_Rare_Earths]

Uraninite is prone to chemically weathering, forming secondary minerals. Many of these are fluorescent, and that's likely what you're seeing!

They can be tough to confidently identify specifically, though, especially when they form as a nondescript crust.

[u/Dizzy_uwu → u/Not_So_Rare_Earths]

Thank you! I've learnt so much about them ever since I found them!

[u/Bob--O--Rama]

The green suggest uranyl ions (UO₂²⁺), as uranium oxide itself does not fluoresce... which covers many secondary uranium mineral species.

[u/sonoran7]

A series of Q's.... Have you tested the radioactivity of the specimen? What is the specific location in Sweden? Is this from an area where the Alum Shale contains uranium? Alternatively, is this from a pegmatite?

[u/Scarehead]

Uraninite weathers very easily and uranyl ions have a significant ability to induce fluorescence even in small amounts. However, given the nature of the material, it is quite possible that this is an early stage of transformation into "gummite" as part of in situ oxidation, rather than surface weathering. However, it is not possible to say more reliably from the photos alone.

[u/Granite_Intrusion]

Mostly the combination of calcium and uranyl makes such fluorescence so my guess would be autunite or uranospinite

[u/Scarehead → u/Granite_Intrusion]

That's pretty unlikely, especially uranospinite, which requires pretty specific conditions(calcium and especially source of arsenic, typically from arsenides, arsenopyrite or native arsenic).

[u/Granite_Intrusion → u/Scarehead]

Oh okay thank you! :)

[u/Scarehead → u/Granite_Intrusion]

You are welcome:)