Really lamination i know they can occur on coins as old as this.Haven't see much on pre 20th century coins.
physics-fan3.14, posted: "I agree, it is a planchet flaw. If it flaked off, it would be a "lamination," but it is retained. Actually, it is a planchet flaw. As soon as the metal separated on a plane, it became a lamination. If the split part broke off, it would be a detached lamination. paddyman98, posted: "Cracked Planchet." A cracked planchet is a planchet flaw. Cracked planchets GENERALLY are vertical cracks whose two edges eventually come together and close. The peeling on this coin runs along the rim when it reaches the edge.
Put some coin care on that reverse and let it soak a short time. Then remove the green crud around the letters.
I may do that some day. Been thinking about it for over 20 years. I have a lot of old copper that could use a bit of help.