False Iridium finds

anachronism

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Guys

A few know but it's not been publicised however Deano, Nickvc, Goran, Kurtak, and Patnor are all spending a week together here in the UK having a bit of a "get together."

The information that's coming out as we share things face to face is pretty incredible and there's already one major thing that needs to be said for all the people "discovering" Iridium ores.

Goran bought some samples with him that he wanted us to run by the XRF.

One of the samples read over 80% Iridium when in reality it's 80% Arsenic. This also applied to every other ore sample that contained Arsenic. These have already been assayed elsewhere (and are Arsenic)so we would suggest that anyone who discovers miraculously high levels of Iridium should obtain other analysis to back it up.

This may well explain some of the recent "finds."

Regards

Jon
 

g_axelsson

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I'm having a wonderful time here. The only thing I don't like is the cold, I'm disappointed that Jon couldn't made the weather a bit warmer when we all are here. :mrgreen:

Here is a picture of my metallic arsenic ore and the results I got from Jon's XRF.
Arsenic XRF.jpg
The silver was expected, the gold I'm suspecting is another false measurement, possible antimony that is well known from other arsenic specimens from this mine. The iridium is obviously the arsenic that the bulk of this specimen is made up of.

Göran
 

rickzeien

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Who Carrie's arsenic with them on a trip? Careful Jon don't drink the tea!

LOL. Seriously... Thanks to all for sharing.

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snoman701

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I imagine the density is a dead giveaway.

But I'd be interested to see the results out of precious metals mode. Does your gun recognize zinc in precious metals mode? I know for a while they didn't.

If you can download the spectra to the computer, you should be able to see it a lot closer to 10.5 (Arsenics Ka1 line) than 10.7 (Iridium's Lb1 line). Although I can't remember the spectral resolution.

And Rick...why WOULDN'T YOU carry a cool rock on a trip? lol Most of us prefer to vacation to places where we can pick up cool rocks on the ground, or talk to others about cool rocks.

Have fun and don't drink too much.
 

snoman701

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g_axelsson said:
The silver was expected, the gold I'm suspecting is another false measurement, possible antimony that is well known from other arsenic specimens from this mine. The iridium is obviously the arsenic that the bulk of this specimen is made up of.

Göran

Actually, the gold is probably overlap on the arsenic again. 11.4 Au 11.7 As. It's seeing Arsenic and assigning it to the two most likely elements seen in jewelry.

https://www.bruker.com/fileadmin/user_upload/8-PDF-Docs/X-rayDiffraction_ElementalAnalysis/HH-XRF/Misc/Periodic_Table_and_X-ray_Energies.pdf
 

g_axelsson

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Snoman, that is probably the explanation of the gold content. The ore in this mine actually run at 1g Au/ton at the average (yearly production of 300.000 tons of ore over 5 years time) but I've never seen a specimen with gold in it that you could actually see. The mine geologist told us that the gold were often encountered with the galena (lead ore) but it was spread through the main ore too. The mine was a copper - zinc mine so the gold were a bonus... 1.5 tons of bonus. :mrgreen:

And to explain why I'm bringing arsenic to a party... I wanted to know the silver grade as I got close to 40-50 kilos of arsenic that I collected in that mine. I'm selling it as mineral specimens and I don't want to sell it below the value of the content. :twisted:
... not very probably, I've sold one 20 gram specimen on ebay and the auction ended at 20 dollars... I can live with that.

Göran
 

snoman701

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Lino1406 said:
No Pb at La 10.55?

Not in precious metals mode I guess.

It’s really hard to interpret xrf spectra without a spectrum! That’s what really limits the usefulness of the guns.


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g_axelsson

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I'll give it another go and see if I can get a better spectra or at least a list of what it thinks is in that rock.

The main point in any case is that we now know what's up when someone comes here, claiming they found an iridium mine.

Göran
 

Lino1406

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For information, the iridium mine I know, contains 90% Fe, probably as mainly oxide, and 1/2 0/00 Ir, seen for the naked eye as sparkles
 

Platdigger

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Ok but, 1/20 percent would be 1 pound per ton.

One part per million would be one gram per 2200 pounds or 1000 kilos

so still unclear to me, sorry if I am being dense.
 

imrani

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g_axelsson said:
I'll give it another go and see if I can get a better spectra or at least a list of what it thinks is in that rock.

The main point in any case is that we now know what's up when someone comes here, claiming they found an iridium mine.

Göran

Hello to all my question is did you try this rock in mining mode with xrf?
 

g_axelsson

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No, I didn't test it in "mining mode" as it only have the library for precious metals.
It seems to detect Au, Ag, Pt, Pd, Rh, Ru, Ir, Cd, Ga, Ge, Ni, Co, Fe, Cr, Zn, In, Sn, W, Cu, Mn, Ti and Pb.

I don't know but I'm guessing that a full range library would cost a bit of money. But that is what you would need for analyzing rocks and even some e-waste.

So anyone using an XRF that is in precious metal mode would probably see arsenic reported as iridium.

Göran
 

galenrog

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Our favorite Swede is, of course, correct.

I have met several professionals over the years that use XRF devices. The models they used were purpose built for the particular industry. For example, the local scrapyard used one to identify a specific range of industrial alloys, mostly those high in nickel. It has no precious metals in its library, and is, therefore, useless in analyzing jewelry or other precious metal items.

I also have a pawn shop owner nearby that uses an XRF to help determine precious metal content. His XRF has a library sufficient to determine PM alloys, and little else. His device would be useless in identifying cupronickel alloys

Both hardware and software of XRF devices are equally important.

Time for more coffee.
 

snoman701

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g_axelsson said:
I don't know but I'm guessing that a full range library would cost a bit of money. But that is what you would need for analyzing rocks and even some e-waste.


Göran

Depending on the model, likely not even offered. The spectral resolution isn’t good enough on the handhelds, and you still have to have manufactured standards that are close to the alloy in question...or, know what should be there.


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