First find ever - need help identifying

[Saasquatch]

This looks like it could be a button, but there is no shank or anywhere it looks like it had a way to be attached (back is smooth.) The engraved inner circle is raised from the wider circle around it. It looks like it's about the same size, or slightly smaller than a dime. Any other ideas what it could be?

Found it at the site of an old estate site (1870s - 1940s era) in the Hudson Valley area. The Astor's were in the area of the estate, but that's probably a stretch that it belonged to them. Trying to figure out what this is, and any help would be much appreciated!

 

[del]

Clean the back as best you can and show us ( i suspect it has a solder or brazed mark where the attachment was) it could be a few things like a cufflink button , tie tack or lapel pin .

 

[Saasquatch]

Clean the back as best you can and show us ( i suspect it has a solder or brazed mark where the attachment was) it could be a few things like a cufflink button , tie tack or lapel pin .

Ok will do as soon as I can. Going to check the forums for the best way to clean it up safely. Thanks!