Button i think

[gmanlight]

I posted this on whatsit a month ago .I found it at a old cellar hole were i have found many flat buttons
and 2 knee buckles dating to the late 1700s The front is very smooth with beveled edges . The back had what looks like a
hole were the shank was mounted in a lead alloy backing . Thanks for the look Mike

 

[gmanlight]

Very little cleaning was needed . I just washed it and it looked like this

 

[vayank54]

If it has a lead filled back I would lean toward it being some type of harness rosette and precivil war