1843 CCC8R Sheffield Plate Over A Probable Copper-Based Alloy Host Medal Turn Die Axis

Maybe a contemporary counterfeit
It will be interesting to see the posted test results.

The plating seems to be quite thin, and over the past 100+ years, there may have been some transmigration of silver and copper across the plating interface, resulting in less silver purity in the darker surface areas.

Jeff Rock: A known counterfeit - the assayer is for 1842, not 1843, and the reverse die was used on others and Bob Gurney has nicknamed it the "Beautiful Eagle" die.

Cap & Rays were of great interest at CICF so I bought maybe eight or so from a dealer from Arizona along with the large book he had in the case.
After much help from experts also present in this thread, I was able to make a nice bundle of photos and notes for placement in the binder.
The coins were of such great interest, I wanted to buy the remainder of what the dealer had that I didn't buy the first time.
I sent a message after the show to the dealer in Arizona, but didn't get a reply.
There's something special about these coins that make them wonderful to collect and study.