How is this possible?

It's on Great Collections right now. 2017 is a year that is nowhere near the last time they made cents out of copper, which I believe was 2009.

 

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A copper blank probably got stuck in the machine and finally broke free and was minted years later.

 

FYI…1982 was the transition year from copper to copper plated zinc cents.

 

But in 2009 there were cents struck in bronze as a commemoration of Lincoln's 200th birthday (and the Lincoln cent's 100th).

 

Yes but not for circulation as I recall.

 

Thats not even the correct composition. It should be 95% copper and 5% zinc.

 

Did they quote the copper coating percentage?

 

Hmm. I assume the composition on the label is from XRF. I wonder if XRF gives inaccurate readings on bronze because the copper would block the fluorescence from the zinc... no, I don't think that makes sense. If PCGS found they were consistently getting <1% zinc readings on coins that were supposed to be 5% zinc, surely they'd do something about it.

 

There shouldn't be a copper coating on a bronze planchet.

 

Not all the 2009s are copper. Most of them are zinc.
There were some that are 3.1g and should have a more matte finish.

 

This coin was reported to be significantly overweight (2.97 grams, as I recall). That creates the possibility that this cent was struck on a zinc planchet with an excessively thick layer of copper plating. I have such an example that weighs 2.9 grams. It's possible that the XRF device wasn't able to penetrate very far into the copper plating, generating a reading that is mostly copper. This coin would have benefitted from a specific gravity test or even a crude "ring" test.

 

That seems more plausible.

That's one downside of the increasing availability of XRF - people tend to take it as gospel, even in cases where it's not necessarily reliable.

Quick Googling indicates that XRF can see maybe 0.1mm into copper. Surface area of a cent would be around 6 cm^2, so 600mm^2, times 0.1mm coating thickness would make 60 mm^3 of copper, or 0.06cm^3, which would weigh... a bit over half a gram. Which is awfully close to the excess weight for this coin!

 

There are other non-invasive ways to test metal content, such as electrical resistance. Surely PCGS would have been aware of this and tested it with more than XRF and scale. But assuming it is actually copper, I would suggest mint employee shenanigans rather than an odd foreign planchet accidently getting loose in the machinery.

 

The mint made some, but I don't think they were meant for circulation. The circulation ones were made of the same copper-plated zinc, though I did find one in circulation a while back.

 

I did a Google search today that if there were any coins anywhere with that composition and it came up zero.

 

The U.S. Mint has not produced foreign coins for decades.

I doubt that PCGS only relied on XRF to determine the composition.

To date, this is the only certified example of a 2017 Lincoln Cent wth a composition of 99% copper.

No, I am not the consignor.

 

Actually, I mis-typed the weight. I think the reported weight was 2.87 grams.