1982 Lincoln Cent wrong alloy

@Robert lyons Is that a Thermo Scientific Niton XL2 GOLDD analyzer ?

 

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I took the coin to an assay office and the coin is made out 54% zn, 34% cu, 10% sn and misc 2%. This is off of a big machine and not a handheld. I showed the coin to an expert and he tells me that the coin is not plated and that it was struck and not cast. He was not familiar with any prototypes from that year. So the question I ask all of you is whether anyone is familiar with a prototype from that year or this coin itself.

 

I think you will have to be more specific about what kind of expert looked at the coin, and what did he or she do to come to this conclusion. What tests were performed on the coin? It is necessary to know this to figure out how much trust to put in his or her opinion.

 

If that is the metallic makeup, then I suggest you buy your friend a new machine for Christmas that can read metal content properly.

 

If they did a non destructive test like xrf or EDS on an SEM they DID NOT analyze the entire composition, only the surface. At best, you are only getting data from a few hundred microns below the surface. Your analytical expert should have been well aware of the limitations of the equipment and I'm surprised he\she didn't explain this to you.

As I wrote in post #18, the composition you posted is consistent with a coin that was zinc plated after it left the mint and The new data confirms that. The Sn is likely from the Zn that was used in the plating bath.

You have a post mint plated cent. The analytical data supports this and the opinions of knowledgeable numismatic experts on this thread (including one of the world's leading experts on error coins) supports this.

 

He explained that he was running the same tests that he runs on the machine to analyse and buy thousands of dollars of gold a day.
Oh well. Thanks everyone for the input.

 

And the machine correctly identified this cent as not gold.

They're cool machines, and I'd love to have one, but it won't turn me into an analytical chemist. Him, either.

 

Zinc coins are made out of zinc with a thin copper plating. They don't put anything in the zinc. It's zinc.
It's not alloyed as I already posted.
If Fred W. already posted in this thread, he knows more about it than your gold analyzer guy.

 

Actually they do, they put a very small amount of copper in it because it helps the copper plating to adhere to the zinc.

The copper and zinc readings are pretty much what you would expect to see from an XRF test on a normal copper plated zinc cent. The Ni and Ir readingsare probably from whatever plating was used on the cent post mint.

The fact that the first test showed NO Sn, and the second shows 10% Sn tells me there is something wrong with one of the tests. I can believe the second test if the cent was plated with tin post mint. That would give you the readings you are getting from the second test and the silver color. I'm surprised that the first test didn't see any tin though.

 

@Conder101 Check out his pic of the readout in post #8. The program listed Sn over some of the peaks on the chart, but the readout listed Ir. I think the discrepancy is due to the algorithm used by the handheld unit and I think the Sn was just part of the Zn used in the plating bath.

 

here's a resource. hope it helps you get past the generalized PMD evals. https://forums.collectors.com/discu...opper-zinc-cents-without-weighing-them#latest

Toss them against an anvil. Bronze will "ting" and zinc will "thunk."

 

It's still a plated coin.

The 'other' elements the machine is reading
is probably the plating.

The coin did not leave the US Mint looking like that, imo

 

Hmmmmmmmmm perhaps you could share his identity, I have some gold plated tungsten he might be interested in

 

Yeah, unless you're driving it with a cyclotron, I don't think an XRF meter is going to pick up on a tungsten core under a few hundred microns of gold.