Lamination and planchette error? 0

[R__Rash]

What would be the under the thin copper layer that it is peeling from?

[Coinbuf]

Corrosion and verdigris.

[RWB]

The nominal alloy for 1918 cents was 95% copper and 5% tin and zinc. During melting copper sometimes oxidized due to careless handling and this produced cupric oxide, also known as "fire scale." If a small amount of this remained near the surface of a planchet, the pressure of striking could cause the coin to split or delaminate. The result might be a thin leaf of copper with an irregular mass of black cupric oxide under, or next to it. Your photos are a little fuzzy, and color balance if off, but I suspect that is what happened to your coin.

There is limited collector demand since each is a unique example.

[RWB]

On this coin it might also be from exposure to acid; however, sharp edges near the base of the bust suggest mechanical rather than chemical causes.

[R__Rash]

On 1/5/2022 at 5:16 PM, RWB said:

The nominal alloy for 1918 cents was 95% copper and 5% tin and zinc. During melting copper sometimes oxidized due to careless handling and this produced cupric oxide, also known as "fire scale." If a small amount of this remained near the surface of a planchet, the pressure of striking could cause the coin to split or delaminate. The result might be a thin leaf of copper with an irregular mass of black cupric oxide under, or next to it. Your photos are a little fuzzy, and color balance if off, but I suspect that is what happened to your coin.

There is limited collector demand since each is a unique example.

It is the thin leaves of copper surviving the decades that made me set it aside years ago when I found it in my wife’s Folgers can of change.  Thanks. 

[RWB]

It's a nice find and certainly of interest. It also raises just the questions you asked. The difference is that through improved research, and especially much better information on production details, we can offer a better, more complete response. [If you borrow a copy of my book, From Mine to Mint, you'll get a bit of the flavor for more modern research knowledge, and information.]

Edited January 6, 2022 by RWB

[R__Rash]

As always, I appreciate all responses. Thank you to both of you, @Coinbuf and @RWB for your response.

[Zebo]

On 1/5/2022 at 9:21 PM, RWB said:

It's a nice find and certainly of interest. It also raises just the questions you asked. The difference is that through improved research, and especially much better information on production details, we can offer a better, more complete response. [If you borrow a copy of my book, From Mine to Mint, you'll get a bit of the flavor for more modern research knowledge, and information.]

I just started reading FMTM and so far I am enjoying it very much. It will take some time to read it, however since I do not travel much anymore (favorite reading time). It actually moved up many positions on my reading list because I was planning on a long trip (now canceled). I also like that it has a dvd to search. I haven’t had a reason to use that yet, but hopefully will.