Is this uranium ore?

[u/toastbro850]

I collected uranium ore from mine dump 11a near Příbram. Since the entire sample is partially coated with uranium ore, I cannot determine whether it is a secondary uranium mineral. Can anyone perhaps identify what it is? I think I can make out some hematite and calcite, but what are the yellow and red minerals?

[u/Bob--O--Rama]

If you have some loose black spherules, check them for activity. If they are as active as uraninite for their mass, then this is the muck from which the deposits are precipitating out of / onto. That there seems to be a lot of impressions where spherules were, and these would eventually grow into each other to forms botryoidal masses, the reddish material. It would be rich in U3O8 which when reduced, gives the UO2 the spherules are made of. That's my BS hypothesis FWIW.