I know this is a longhorn shot but does anyone have any ideas on which large cent this is? The comparison coin is an 1855 large cent. Any help is really appreciated.
You seriously think anyone can identify anything on that piece? It is so thick with corrosion that all we can see is a round shape. That is the joke.
It was found under the floor boards (in dirt) at a national historic building. I’m trying to date the section of the building.
In all seriousness - the ancients guys, or metal detecting guys, have some really good conservation techniques that can help remove that encrustation. Until then, these pictures just don't show enough to be able to help you in any meaningful way.
Sorry, but it is so corroded, there is nothing identifiable. Huge maybe, but I might be able to be convinced its a US large cent. Maybe the top pic is a later date reverse that's upside down but the pic of the other side? Could be anything. US?, foreign?, hardware? Outside of serious, professional conservation, IMO, it will never be more than a corroded disk of copper. Best of luck
One technique I used with some of my finds like this was to cut a slit in a raw potato and leave the "crusty critter" coin in there overnight. (Actually, there's no need to cut a slit- you can just shove the coin into the side of the potato.) The starch in the potato will leach some of the corrosion off of the coin. Now, there's a chance it could also change it to a funky color, but at this point, since you're already starting from such a corroded example, there's little downside risk of further ruining it, and it might help parse out some more details to aid in identification. One thing I would NOT recommend is electrolysis. I made that mistake with my first dug large cent, which was barely identifiable by type as a 1796-1807 Draped Bust coin. I hooked it up to electrolysis in an a similar attempt to maybe date it. But I accidentally "burnt it up" in the process, leaving it a featureless slug. The metal was just not stable enough to run an electrical current through it without damaging it.