URAL MINERALOGICAL FESTIVAL, July 3 to 21, 2019, in Yekaterinburg City, Ural region, Russia
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 Post subject: Agates from Argentina. SOUTHWEST REGION : Ghost agate
PostPosted: Sun Mar 03, 2019 10:00 pm 
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Ghost agate

Ghost agate deposit is located 20 Kilometers north of Petrified Forest National Park in Santa Cruz Province, Argentina.
This agate is found loose on the ground or semi buried under decompose Andesite.
The nodules are round or almond shape with very distinctive fortification pattern in white color suspended in clear chalcedony.
Some special features inside this agate are moss, plume, tubes, and curtains pattern.
The agate age is Jurassic, (160 million years old)
Small percentage of nodules are fluorescent green color under UV light short wave.


Attachments:
File comment: Same specimen of Ghost agate as the previous one under UV light short wave.
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File comment: Ghost agate cut and polish
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IMG_2933.JPG [ 2.68 MiB | Viewed 664 times ]
File comment: Ghost agate cut and polish
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IMG_2965.JPG [ 2.94 MiB | Viewed 664 times ]
File comment: Ghost agate cut and polish
IMG_2913.JPG
IMG_2913.JPG [ 2.63 MiB | Viewed 664 times ]
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 Post subject: Re: Agates from Argentina. SOUTHWEST REGION : Ghost agate
PostPosted: Sun Mar 03, 2019 10:17 pm 
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Is this another example of uranium contamination?
What is the source of the uranium?


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 Post subject: Re: Agates from Argentina. SOUTHWEST REGION : Ghost agate
PostPosted: Sat Mar 16, 2019 2:19 pm 
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The green fluorescence color in this material is different than the other fluorescent green color agates that had been in contact with uranium salt.
I'm not aware of Uranium deposit near this ghost agates.
I don't think the fluorescence in ghost agate is due to contact with uranium salt.
What cause the fluorescence in ghost agate is unknown yet.


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 Post subject: Re: Agates from Argentina. SOUTHWEST REGION : Ghost agate
PostPosted: Sat Mar 16, 2019 2:33 pm 
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With that color I think uranium is inevitable, and it doesn't take much. Uranium is highly mobile in the hydrothermal fluids that agates form from so it's pretty easy for it to get in, and the source itself might be distant or long since eroded.

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