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Foolingest Fools Gold

Posted by Rolf Luetcke  
Rolf Luetcke June 12, 2018 04:17PM

I wanted to post this since it is the closest to looking like gold that I have ever seen for a "fools gold" material.
I have been looking for a piece with native gold from the Johnson Mine in SE Arizona for years. It is in the commodities list for the mine but not listed as a mineral. I know it has the potential of being there.
I used to teach an adult education class in telling gold from fools gold and I covered all the common ones like pyrite, chalcopyrite, iron coated quartz and others. Even mica can look a lot like gold.
My wife found this piece from the Johnson Mine and thought it looked good for possible gold. I split the piece and it had nice quartz, hematite, chalcocite, chalcopyrite and more. On one corner was the material in the photos. I looked as close under 40 power I could and both Mary and I thought it was gold.
Next day I put in my 20x eye pieces and at 80 power it was still hard to not say it was gold. It didn't loose the color no matter which direction one turned it, needle test didn't splinter it but only parted the material. It is small, about 3mm field of view but after a real study of the piece I did finally see a tiny sheet and my disappointment was there. The piece was actually mica but in a way that I had not seen, the mica was super thin and coated all the rough surfaces on the quartz. Sure had me fooled.
I thought I pass this little story along for people who love looking for gold and this is one that fooled even me.
Uwe Kolitsch June 12, 2018 04:31PM
Possibly arseniosiderite?
Rolf Luetcke June 12, 2018 04:50PM
I have seen a lot of the golden colored mica at this location and never arseniosiderite from there. I finally did see the micacious habit in one spot and that told me it was the mica but it had me fooled for a while before I finally saw it was actually mica. Of course only actual analysis at a lab would say for sure but I am about as sure as can be it is only mica. Never had one that looked so much like gold.
Doug Daniels June 13, 2018 01:34AM
Well, don't just toss it until it's been analyzed.......
Alysson Rowan June 13, 2018 08:39AM
Doug Daniels Wrote:
> Well, don't just toss it until it's been
> analyzed.......

A piece like this is worth hanging on to, even as a curio.
Larry Maltby June 13, 2018 11:43AM
How about putting it under the microscope and touching it with the point of a needle?

I see you tried that. I read right over that info the first time.

Edited 1 time(s). Last edit at 06/13/2018 11:52AM by Larry Maltby.
Rolf Luetcke June 13, 2018 12:36PM
Some day, maybe, my ton of ? minerals will get analyzed, especially If that Raman in another thread gets affordable.
The piece has been mounted in a perky and is in my box of Johnson Mine minerals. Definitely want to keep it for the reason it fooled me so well.
My wife said it is a very pretty piece with the colors of the mica and hematite and I like it a lot too. Just wanted to post it since it was the best fooler I have ever come across. I find lots of gold and considered myself pretty darn good at telling it from the various foolers but in this case it had me going for a couple of days.
Did try the needle and it didn't break anything off but only pushed it aside so it was another fooling thing. In this case the mica is so thin and covering the quartz matrix it didn't show the foliation except in one spot, where it finally showed itself as mica, only spot I found the typical foliation. There is a lot of golden muscovite at the Johnson, just not quite like this.
Fun piece and I wanted to share.
David Von Bargen June 13, 2018 02:47PM
I have seen a lot of weathered muscovite in sediments that has a very golden color. Cleavage plates and light weight will give it away.
Rolf Luetcke June 13, 2018 09:53PM
Yes, in larger pieces it is absolutely right, this however, was very small and I often find tiny gold in quartz from local mines and weight doesn't come into it at all in those cases. This one, even if it had been gold, wouldn't have added much of anything to the piece. That is one problem with micro specimens but a friend collects micro gold and had not gotten one from this location. I was mostly looking for his sake.
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