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GeneralUraninite Brazil - searching for exact location

29th Sep 2014 04:36 UTCChristopher O'Neill

02135190016021638778765.jpg
Hello,


These are specimens of uraninite on and within childrenite crystals from Minas Gerais, Brazil.


We are attempting to find a definitive location for these specimens


Is there anyone out there, who is familiar with the MG region, that has seen similar specimens?



02932430015998129285740.jpg



Regards,

Chris

29th Sep 2014 10:44 UTCLuís Martins 🌟

Very interesting. How was the uraninite identified?


I have never seen a sample like this, but the number of localities in Brazil capable of producing Childrenite like that is not large...

29th Sep 2014 15:53 UTCChristopher O'Neill

03293710016021638778310.jpg
Luis,


These are from an old Louis Zara collection. The only confirmation I could make is that they are radioactive and you can see a round alteration hole in the lower right of the top photo. I could send a sample out for EDS to verify but I thought I would at least find another example of this somewhere.


I have been checking images of other specimens to see if something like this was evident but overlooked. I found this one, however there is no way to tell what the black stuff is and I'm now wondering how to tell the difference between childrenite, eosphorite and ernstite


Ernstite ps. after childrenite - Boa Esperança Claim, Linopolis, Divino das Lananjeiras, Minas Gerais, Brazil





The eosphorite in the following link has black inclusions........


http://www.mindat.org/photo-5854.html

29th Sep 2014 18:29 UTCRob Woodside 🌟 Manager

The black spheres look more like Thucolite or pyrobitumen

29th Sep 2014 19:13 UTCChristopher O'Neill

05105780016021638774467.jpg
Rob,


If it is a mineral other then uraninite, it seems more like Baddeleyite from the MG region.


30th Sep 2014 18:02 UTCVitya

This is quite an interesting specimen but I do not believe it is Uraninite. Most of the Uraninite specimens I have seen do not form such a habit and even the Uraninite specimens from Minas Gerais are more of a crust or massive material. Here is an example of a Uraninite I have found from the Minas Gerais area:


http://www.mindat.org/gallery.php?loc=387&min=4102


How was the radioactivity also measured or verified. I would recommend to use a good Geiger counter and Uraninite is usually very active on the display from the ones I have seen in Haliburton/Hastings Co. Being radioactive doesn't necessarily indicate it is Uraninite it could be one of the other species listed here:


http://www.mindat.org/loc-387.html

30th Sep 2014 18:31 UTCRob Woodside 🌟 Manager

Christopher, I think an EDS would help a lot. Once we know what it is, some knowledgeable person might know where it is from.:-)

30th Sep 2014 19:10 UTCChristopher O'Neill

Vitya and Rob,


I use a Ludlum Model 3 with a 44-9 probe so its a pretty good counter.


And Rob, I agree that this should be sent out for EDS, I have a number of items ready to send up to Kerry Day, so I will include this as well. It could be very interesting if is NOT uraninite as well.


I was just hoping there were similar specimens out there, like this one.


I'd like to thanks everyone for their feedback,


Chris

30th Sep 2014 23:41 UTCChristopher O'Neill

Although if anyone out there has any additional info, please chime in............
 
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