We have a Cast Iron salvaged round Vintage item.  This is a great item to repurpose/recycle.  It is a mix of cast iron and rust.  There is a 3/16" center hole around is an ornate design .  It measures about 4 7/8" across the center round x about 1 1/4" in H.   I'm not sure what this came off of.

Cast Iron Salvaged Round Recycle / Repurpose Vintage