Hydrochloric acid on gold, is this suppose to happen?

corylane

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Jan 20, 2013
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I found some flakes is an area that I did not expect to find any traces of gold & I wanted to test it to see if it was real, so I dumped some hydrochloric acid on one of the flakes in a shot glass, waited a couple minutes, swirled it around a bit, waited about 10 minutes total, swirled some more. It never bubbled, discolored or anything else. It just looked like a normal flake in water until I tried to smear it out with a cotton ear swab. As I drug it up the edge of the glass with the swab, it split into 3 different layers of the same shape of the flake. It was as if there were 3 flakes layered on top of one another & the acid broke them apart, but still had a very strong golden glimmer. I should also mention that this was the first time I had ever used a gold pan & have virtually no experience with hands on gold, except for jewelry. Needless to say, I was tickled pink when I pulled 5 flakes with my first panning. I also had just as many silvery flakes in the pan & I didn't bother extracting all of them.

My Questions: Has anyone else experienced this with flakes "un-layering"? Does it sound like I'm describing real gold? & does gold sometimes appear silvery in color when its in the pan? I appreciate anyone's expertise.
 

Good Morning corylane,
And welcome to Tnet. I have never used any acid on anything I've found so someone else with that experience will need to answer that portion of your question. Gold does not look silvery unless it has mercury on it. To me the splitting apart into layers does not sound like gold. Another test, with the material you have on a hard surface press on it with say the edge of a screwdriver or similar hard object. If the material bends, flattens when stretched or in general stays together then it could be gold but if it breaks it is something else like mica. I'm certain that by the end of the day someone will come on here with more information for you...............63bkpkr
 

Could be iron-pyrite,'fools gold'. It would break up on impact like 63bkpkr said. Here's your test. pyrite will burn if you apply heat with a torch, while gold will melt. Pyrite sometimes appears gold in color, and sometimes, silver. I never tried acid on it. Frank

hand print-2_edited-6.jpg
 

I would say that is not gold. I have never acid tested flake gold, But I have tested jewelry and even thin gold rubbing on a touchstone won't react like that. And I would think that flake would be thicker than the rubbings.
 

Assuming your flake is metal. If it didnt fiz or bubble in the acid, then its pure gold. Ussually if its gold it will still fiz a little becasuse small amounts of other metals in it. . Hope that helps. When testing with acids use a dropper. Remember if its not metal then muriatic acid with have no reaction with it.
 

Probably not metal. Mica and biotite resemble gold but will come apart in layers.
 

Gold is unaffected by air, water, alkalis and all acids except aqua regia (a mixture of hydrochloric acid and nitric acid) which can dissolve gold. Gold does react with halogens. It will, for example, react very slowly with chlorine gas at room temperature to form gold chloride, AuCl3. If gold chloride is heated gently, it will decompose to release the pure elements again.
 

Gotta ask did you find the suspected gold under the black sands or on top of them? you mentioned a lot of silvery flakes, were they under the black sand or on top?

As to how you described it breaking up... no that's not typical. For Mica yes and for pyrite it can happen. One thing you can do is just put the suspected gold in a small vial of water and swish it around... if it keeps floating its mica. Gold will just drop. For pyrite a crush test will work.
 

only thing I have ever seen split in layers is muscovite mica(its the shiny stuff in some abrasive cleaners).I have seen mica look golden or silvery.
The acid may have been a weak blend...old and or deactivated.I dunno...I never acid tested mica.

cheers
 

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