Today we call them "Sintered" or "Mis-annealed" planchets.
In the 'old' days, they were called 'Copper Wash' coins.
It's the result of the planchet, before it was struck, being overheated in the annealing process - literally Sintered.
Retired Collector & Dealer in Major Mint Error Coins & Currency since the 1960's.Co-Author of Whitman's "100 Greatest U.S. Mint Error Coins", and the Error Coin Encyclopedia, Vols., III & IV. Retired Authenticator for Major Mint Errors for PCGS. A 50+ Year PNG Member.A full-time numismatist since 1972, retired in 2022.
It was struck on an improperly annealed planchet. Exposure to excessive heat or prolonged heat caused the constituent metals (copper and nickel) to migrate and segregate out into relatively pure layers. Copper tends to accumulate on the surface. The terms "sintered plating" and "copper wash" should be discarded as they refer to theories that have been falsified.
Mike Diamond is an error coin writer and researcher. Views expressed here do not necessarily reflect those held by any organization I am a member of.
Comments
"Mis-annealed" planchets.
In the 'old' days, they were called
'Copper Wash' coins.
It's the result of the planchet, before
it was struck, being overheated in
the annealing process - literally Sintered.
I've seen a few that have very obvious spots of copper, but none like this. Very very cool.
edit: but i would take the guy above me's word for it
purdy cool lookin'
Too many positive BST transactions with too many members to list.
Steve
The name is LEE!
.oops
R.I.P.