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Mystery of wulfenite Pb(MoO4) from Globe, AZ
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Normally wulfenite is not radioactive but I found one a couple of years ago that is slightly so and I added it to my collection.? The most curious thing about this specimen is that it is pitch black instead of the normal orange: Later I found the normal orange version (not radioactive) and held onto that because I thought it might be interesting to compare it to the black specimen someday. Well, that day came yesterday and the results are attached.? The red and blue are scans of the crystal side of each specimen.? As expected they both contain Pb and Mo.? The difference was the addition of Mn in the black specimen. So I go to mindat and select the Globe Mine page where it lists all the minerals that have been reported and click on the Mn button to restrict that list to just minerals containing Mn: Lo and behold a mineral called Coronadite Pb(Mn4+6Mn3+2)O16 pops up that can form a pseudomorph after wulfenite by Mn replacing Mo:
So the mystery appears to be solved.? Just to be sure I scanned the matrix side of the black specimen which appears to be the normal botryoidal form of coronadite.? Sure enough it has the Mn but no noticeable Mo. Could I have figured this out without the Si-PIN XRF?? Sure, if I had examined all the minerals from Globe Mine I would have seen that Coronadite was the obvious id.? Sometimes it is not so easy though like the brannerite that I previously reported about.? I am still in discussions with the dealer who insists that the id is correct despite my XRF showing otherwise. Charles 
ThereminoMCA_Amptek_DppMCA_Si-PIN_wulfenite_Globe_Mine_AZ.png
ThereminoMCA_Amptek_DppMCA_Si-PIN_coronadite_Globe_Mine_AZ.png
Amptek_Si-PIN_black_wulfenite_Globe_AZ back.mca
Amptek_Si-PIN_black_wulfenite_Globe_AZ back.mca
Amptek_Si-PIN_orange_wulfenite.mca
Amptek_Si-PIN_orange_wulfenite.mca
Amptek_Si-PIN_black_wulfenite_Globe_AZ.mca
Amptek_Si-PIN_black_wulfenite_Globe_AZ.mca
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Super cool use of XRF Charles! Do you have any radioactive Smithsonite? Geo>K0FF ----- Original Message ----- From: Charles David Young <charlesdavidyoung@...> To: [email protected], Mike Loughlin <loughlin3@...> Sent: Sat, 15 Feb 2020 09:45:42 -0500 (EST) Subject: [XRF] Mystery of wulfenite Pb(MoO4) from Globe, AZ Normally wulfenite is not radioactive but I found one a couple of years ago that is slightly so and I added it to my collection.? The most curious thing about this specimen is that it is pitch black instead of the normal orange: Later I found the normal orange version (not radioactive) and held onto that because I thought it might be interesting to compare it to the black specimen someday. Well, that day came yesterday and the results are attached.? The red and blue are scans of the crystal side of each specimen.? As expected they both contain Pb and Mo.? The difference was the addition of Mn in the black specimen. So I go to mindat and select the Globe Mine page where it lists all the minerals that have been reported and click on the Mn button to restrict that list to just minerals containing Mn: Lo and behold a mineral called Coronadite Pb(Mn4+6Mn3+2)O16 pops up that can form a pseudomorph after wulfenite by Mn replacing Mo: So the mystery appears to be solved.? Just to be sure I scanned the matrix side of the black specimen which appears to be the normal botryoidal form of coronadite.? Sure enough it has the Mn but no noticeable Mo. Could I have figured this out without the Si-PIN XRF?? Sure, if I had examined all the minerals from Globe Mine I would have seen that Coronadite was the obvious id.? Sometimes it is not so easy though like the brannerite that I previously reported about.? I am still in discussions with the dealer who insists that the id is correct despite my XRF showing otherwise. Charles |
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I do not have radioactive Smithsonite in my collection.? If there is such a thing it is probably U in the matrix. Charles On Sat, Feb 15, 2020 at 8:13 AM <GEOelectronics@...> wrote:
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OK I have one. It needs a good testing with this updated gear, then I can send it for you to test and analyze. One thing I'm curious about is radium replacement in a crystal. This is really obvious in Radio-Barite, and in the phospho-gypsum deposits of the eastern central Florida. I do have a large sample (actually a large Marinelli beaker full) of the Florida stuff In collected from the famous "piles" in Mulberry Fl. No radiobarite here tho, it's my own fault, at one time at a gem show I was tracing radioactive samples and ran across a beautiful deep beer-bottle brown crystal cluster, being guided to it by the pocket Geiger, but Iit was in the beep mode (which I can't hear) and the noise raised the dealer's curiosity. He asked me what that noise was, and being new at this, I told him the truth. He would not sell me at any price.....usually it goes the other way, collectors are happy to be shed of the stuff.From now on, vibrate only, and if noticed, it's a metal detector for certain types of metal I'm interested in. At that same show but different dealers, the pocket detector sniffed out radioactive fossils, some from the Morrison Formation, and one whale bone that was collected in Florida (which I did buy and have), Later after much research online and on foot, found the source- it was from the phosphogypsum mine in Mulberry. The full story is here: https://www.qsl.net/k0ff/Phosphogypsum/ After that, I found many radioactive fossils from Morrison, many were in museums, and the curators were most interested and more than a little concerned At the Mesalands Dinosaur Museum in Tucumcari, the curator let me into the stacks in storage unit with lots of drawers. He wanted to open each and let me examine the contents, but was taken aback when I demonstrated the fact that I could locate the specimens whit the drawer closed. Geo>K0FF ----- Original Message ----- From: Charles David Young <charlesdavidyoung@...> To: [email protected] Sent: Sat, 15 Feb 2020 11:10:06 -0500 (EST) Subject: Re: [XRF] Mystery of wulfenite Pb(MoO4) from Globe, AZ I do not have radioactive Smithsonite in my collection.? If there is such a thing it is probably U in the matrix. Charles On Sat, Feb 15, 2020 at 8:13 AM <GEOelectronics@...> wrote:
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On Sat, Feb 15, 2020 at 10:10 AM, Charles David Young wrote:
Yes uranium for sure Charles.... Just ran a scan and pinpointed uranium right away by the clear Th-234 peaks and Pb X-Rays like you showed me the other day. Thanks for that. George |
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George are you going to post that scan? Charles El El s¨¢b, feb. 15, 2020 a la(s) 1:39 p.?m., <GEOelectronics@...> escribi¨®: On Sat, Feb 15, 2020 at 10:10 AM, Charles David Young wrote: |
¿ªÔÆÌåÓý
Charles, that is a good piece of detective work. It is probably the coronadite that has the U. We found a small late stage vein of coronadite in one of the samples from Petaca that was scanned with the microprobe, and that contained about 2000 ppm UO2.
That is a pretty rich U-Th district though.
Out of curiosity, I tested a big chunk of manganese ore from the Luis Lopez district near Socorro. It is made up of coronadite, hollandite and cryptomelane. Testing with a pancake probe, sure enough, it is about 3 times background. I did not suspect that.
Steve?
From: [email protected] <[email protected]> on behalf of Charles David Young <charlesdavidyoung@...>
Sent: Saturday, February 15, 2020 7:45 AM To: [email protected] <[email protected]>; Mike Loughlin <loughlin3@...> Subject: [XRF] Mystery of wulfenite Pb(MoO4) from Globe, AZ ?
Normally wulfenite is not radioactive but I found one a couple of years ago that is slightly so and I added it to my collection.? The most curious thing about this specimen is that it is pitch black instead of the normal orange:
Later I found the normal orange version (not radioactive) and held onto that because I thought it might be interesting to compare it to the black specimen someday.
Well, that day came yesterday and the results are attached.? The red and blue are scans of the crystal side of each specimen.? As expected they both contain Pb and Mo.? The difference was the addition of Mn in the black specimen.
So I go to mindat and select the Globe Mine page where it lists all the minerals that have been reported and click on the Mn button to restrict that list to just minerals containing Mn:
Lo and behold a mineral called Coronadite Pb(Mn4+6Mn3+2)O16 pops up that can form a pseudomorph after wulfenite by Mn replacing Mo:
So the mystery appears to be solved.? Just to be sure I scanned the matrix side of the black specimen which appears to be the normal botryoidal form of coronadite.? Sure enough it has the Mn but no noticeable Mo.
Could I have figured this out without the Si-PIN XRF?? Sure, if I had examined all the minerals from Globe Mine I would have seen that Coronadite was the obvious id.? Sometimes it is not so easy though like the brannerite that I previously reported about.?
I am still in discussions with the dealer who insists that the id is correct despite my XRF showing otherwise.
Charles
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¿ªÔÆÌåÓýPlease do Dud ? ? From: [email protected]
[mailto:[email protected]] On Behalf Of Charles David Young
Sent: Saturday, February 15, 2020 12:43 PM To: [email protected] Subject: Re: [XRF] Mystery of wulfenite Pb(MoO4) from Globe, AZ ? George are you going to post that scan? ? Charles ? El El s¨¢b, feb. 15, 2020 a la(s) 1:39 p.?m., <GEOelectronics@...> escribi¨®:
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