Old colonial button??? Need button expert

[Gregg3131]

Found this strange cuff button at colonial site. Shank seems to be connected to rim or possibly bent but I have never seen this style before? Any insight would be greatly appreciated

 

[fyrffytr1]

I think it is an upholstery tack. Is the wire sticking out of the back just bent over or does it form a full loop?

 

[Gregg3131]

It's been ID as a mid 1600s colonial button off a Cossack possibly.