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oxidized gold ??


JOHNM

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went with a friend and i watched him pan and save a piece of something that looked like yellow quartz to me.   he said it was oxidized gold.  it was the last piece of material that was in his pan . you guys seen anything like this? if so could you post a picture cause iv'e been throwing stuff like that away. :idunno:

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Gold does not react with oxygen. Therefore, it does not oxidize. It will get a patina on it like a red or black iron stain. LukeJ found a really cool "black" nugget in GV last year perhaps he can post a pic of it.

Perhaps something else in the quartz is oxidizing...it's not the gold.

 

Dean

PS- I'd keep throwing that stuff away. 

Edited by Dbado1
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Pure Gold does not oxidize, but add some chemical compounds/elements to it and then it can or maybe the addtional elemnets do, here's some info on rare oxidation states of gold, unless your a PHD in Physics I doubt you understand it, I don't!!

https://en.wikipedia.org/wiki/Gold

"Rare oxidation states

Less common oxidation states of gold include −1, +2, and +5.

The −1 oxidation state occurs in compounds containing the Au anion, called aurides. Caesium auride (CsAu), for example, crystallizes in the caesium chloride motif.[40] Other aurides include those of Rb+, K+, and tetramethylammonium (CH3)4N+.[41] Gold has the highest Pauling electronegativity of any metal, with a value of 2.54, making the auride anion relatively stable.

Gold(II) compounds are usually diamagnetic with Au–Au bonds such as [Au(CH2)2P(C6H5)2]2Cl2. The evaporation of a solution of Au(OH)
3
 in concentrated H
2SO
4
 produces red crystals of gold(II) sulfate, Au2(SO4)2. Originally thought to be a mixed-valence compound, it has been shown to contain Au4+
2
 cations, analogous to the better-known mercury(I) ion, Hg2+
2
 .[42][43] A gold(II) complex, the tetraxenonogold(II) cation, which contains xenon as a ligand, occurs in [AuXe4](Sb2F11)2.[44]

Gold pentafluoride, along with its derivative anion, AuF
6
, and its difluorine complex, gold heptafluoride, is the sole example of gold(V), the highest verified oxidation state.[45]

Some gold compounds exhibit aurophilic bonding, which describes the tendency of gold ions to interact at distances that are too long to be a conventional Au–Au bond but shorter than van der Waals bonding. The interaction is estimated to be comparable in strength to that of a hydrogen bond.

Well-defined cluster compounds are numerous.[41] In such cases, gold has a fractional oxidation state. A representative example is the octahedral species {Au(P(C6H5)3)}62+. Gold chalcogenides, such as gold sulfide, feature equal amounts of Au(I) and Au(III)."

 

Want to add to the confustion, read this....

https://phys.org/news/2014-09-decoding-role-gold-nanocatalysis.html

"

Gold's unexpected oxidation activity: Decoding the role of water in gold nanocatalysis

September 4, 2014
Decoding the role of water in gold nanocatalysis
Schematic representation of the lowest energy pathway for CO oxidation on gold-titania catalysts. The water layer on the titania support extends the reaction zone on the gold nanocluster and provides protons that assist in the oxygen more

Researchers from the University of Houston and Trinity University have for the first time provided direct evidence of a water-mediated reaction mechanism for the catalytic oxidation of carbon monoxide.

The work used gold nanoparticles and titanium dioxide as a catalyst to speed the process and determined that water serves as a co-catalyst for the reaction that transforms carbon monoxide into carbon dioxide. While researchers have worked with carbon monoxide oxidation using gold catalysts for years and have realized that water can change the reaction, none have previously been able to fully explain why it worked.

The work is described in the Sept. 5 edition of the journal Science.

"We can say with a high degree of certainty that we now understand the role of each of the components and what they do during this catalytic reaction," said Lars Grabow, assistant professor of chemical and biomolecular engineering at the University of Houston. He and Hieu Doan, a Ph.D. student at the UH Cullen College of Engineering, developed computational simulations to support experiments run by Trinity University chemists Bert Chandler, Christopher Pursell and Johnny Saavedra.

Chandler, professor of chemistry at Trinity, said the work was a true collaboration.

"It took all of us to make it happen," he said. "What we did is to bridge the gap between surface science and computational people. We knew water helped the reaction but didn't fully understand its role. Now we know that water is a co-catalyst for this reaction."

When used in jewelry, gold is prized for its nonreactive properties – it doesn't rust or tarnish when exposed to air or water. And researchers have long known that, despite its reputation as an inert metal, gold nanoparticles can work as a catalyst to speed chemical reaction.

But nobody knew exactly why it worked. Water turned out to be key, even when it isn't explicitly added to the process, Grabow said.

Trace amounts of water drawn from the air drove the reactions on the surface of the gold catalysts, he said.

During the experiments and computational study, the researchers looked at how water, surface hydroxyls and the metal-support interface interacted during carbon monoxide oxidation over a gold-titania catalyst.

"In all cases, an essentially barrier-free proton transfer lowered the overall energy of the system, generating H2O2 or OOH. Once OOH formed, it migrated along the Au particle, allowing atoms near, but not strictly at, the metal-support interface to participate in the reaction," they wrote to describe their findings, referring to the generation of hydrogen peroxide or hydroperoxyl and hydroperoxyl's migration along the gold particles.

Essentially, they found that protons from a thin layer of water stretching across the surface of the catalyst detach from the water molecules and attach to oxygen molecules, briefly moving onto the surface of the catalyst to spur the reaction before returning to the water layer.

Previous models typically focused on individual components of the reaction, Grabow said, making this project the first to pull all of the facets together in a single model that fully supports the Trinity chemists' experimental observations. Chandler said the work could provide a way to produce clean hydrogen from petroleum and natural gas.

Read more at: https://phys.org/news/2014-09-decoding-role-gold-nanocatalysis.html#jCp"https:"

 

 

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I call the yellow rocks at the bottom of my pan uranium.  A yellow uranium ore can be found.  There used to be a few uranium claims around Wickenburg.  I think the company let them go.  I've only found maybe five pebble sized yellow rocks that look like dirty gold until crushed.  If I am correct and it is a uranium ore, there is no commercial value in it at all.

I think the specific gravity of black sands is 5-6 so this "oxidized gold" is any yellow mineral with a specific density greater than that which sinks to the bottom.

 

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7 hours ago, Dbado1 said:

Gold does not react with oxygen. Therefore, it does not oxidize. It will get a patina on it like a red or black iron stain. LukeJ found a really cool "black" nugget in GV last year perhaps he can post a pic of it.

Here's a couple pics of the 'black nugget'.  When I first posted the first pic, someone suggested it might be manganese that makes up the black stuff on the nugget.  After 'cleaning' it in hydrogen peroxide and baking soda solution, the 'black' is gone.  I don't think the black stuff was a patina, more of a coating, or maybe just dirt.  Having a patina would suggest the gold reacted with something else.  I just think the black stuff is another mineral present where the gold precipitated out of solution. 

Once you see real gold in the pan, there is no mistaking it.  Also, anything else that looks 'golden' will most likely react with an acid.

Good luck, keep trying.  When you find it, you'll know.

Luke

20161113_203800.jpg

20161116_101822 (2).jpg

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This is a picture of pitchblende, or a uranium ore.  I think I've seen it a couple of times in the bottom of my pan.  It has a specific gravity of 10, so it would go below the black sand.  When I hear oxidized gold, this is what I think.  It's worthless though.  The processed ore is worth a little, but the ore itself is worthless.

Pitchblende.png

Edited by chrisski
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I have a coffee can full of that vary same stuff.  Large chunks.   The Green is low level radio active.  Low ?  A bunch of Bananas puts out almost as much radiation.  

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