Looks like iron back on that one. Possibly a Navy kepi button.
I found a small iron backed navy button a year or so ago. i didn't think the navy used iron backs on their buttons, but some experts on the American Military Buttons 1775-1865 Facebook Group identified it as a navy kepi button. Again, like you say it could be a brass back covered with crust, but it looks like a two piece button to me.I don't think its an Iron back (I could be wrong though) I think its just has a lot of crusties on them.
I found a small iron backed navy button a year or so ago. i didn't think the navy used iron backs on their buttons, but some experts on the American Military Buttons 1775-1865 Facebook Group identified it as a navy kepi button. Again, like you say it could be a brass back covered with crust, but it looks like a two piece button to me.

Well.... I see a convex two piece with either the back missing and full of dirt, or a two piece with a rusty iron back. I can definitely see the rim where the front was crimped over the back.Two piece? Don't tell me that haha, I see a one piece convex button! I'm starting to question my eyes now![]()