Found this penny at work and immediately caught my eye. The reverse is completely fine... the front seems to have a rim around "In God We Trust" and fades away. What happened with this guy?
wait I've also noticed that there's about a 15 deg misalignment with the reverse side... not sure if that helps any
This is a result of some kind of wear that occurs to the obverse die as it is used. It is sometimes seen on the older copper cents but really became common after the copper plated zinc composition was introduced. It seems to have somehing to do with the flow characteristics of the zinc.
Welcome to the forum Xeno108, As conder said, the "extra rim" on your coin is very common, particularly on 1986-1989 Lincoln cents. Though I must admit, I haven't seen many with the ridge as far down as yours.
It's a form of die deterioration (die wear, die fatigue, die deformation) that's commonly found on copper-plated zinc cents. It does occasionally show up on other denominations, though.
how can a die deteriorate and still leave such strong lettering? not questioning you expertise mike, just interested in the process. thanks, michael
In truly severe cases, the letters are "swallowed up" by the ridge so that they're barely recognizable. The real puzzle for me is understanding what there is about the material properties of zinc that exerts such abnormal stress on the die face. Zinc is a relatively soft metal, but I suspect that under rapid compression it exhibits variable visco-elastic properties and strongly resists the impact of the strike. Just a guess.
Hi, This is complete conjecture with NO facts to back it up. I wonder if this type of thing is caused by the copper reacting in a different way than the underlying zinc during the strike. PERHAPS the copper is forced out to the edge of the coin as the strike occurs. Again, pure conjecture. Have Fun, Bill
Copper plating is very thin. The ridges do not flex when you press them with the point of a toothpick. They are solid. That means the copper conforms to the shape of the underlying zinc. This can only occur if the defect was in the die. The ridges are also repetitive, i.e. they are identical in coins struck by the same die pair.
Bill - Check page 108 in the Nov.14,2005 issue of Coin World. There is a write up on the very same subject.
I think mike diamond is correct. I know polycrystalline zinc composites can exhibit visco-elastic properties under compression, so I would assume that is what is causing the problem.
