I thought you were asking about the mark under the monument, that runs through the U and the N. If you were, I think you are seeing a improperly mixed alloy, or a "woodie" effect. JMHO
Yes I was. And I thank you. I do notice the die of the whole rev. Keeping it. It’s like a touch of a few things. I’m so silly.
The lines are that of a bad medal mixture...what I called a clash maybe as I have a war nickel that is clashed very simular to yours. It may also be not having the coin in hand its hard to tell but it also could be machine doubling. People tend to forget the 5 cent coin was a workhorse ,so mintages were high, In the early 60's a nickel purchased a lot . That many are clueless as to the buying power...as us old members have forgotten a nickel got you a Hershey bar ,a single dip ice crean cone, a pack of baseball cards with Micky Mantel in the pk, or enough penny candy to keep you in a sugar coma all day long.
I was thinking stain or toning. But the improper alloy mix mentioned by P and G would create a woody on a nickel which is what this looks like. I remember buying a Hershey bar for 5 cents, and it was larger than today. Or a pack of 5 baseball cards for 5 cents.
Hey I was a penny candy kid. From Mary Janes when they actually put peanut butter in it. Kit candy. Jaw breakers. Lol. Thank you!
I loved kits banana or chocolate ok folks kits were 1 cent and had 5 small squares of candy. Mary Janes right peanut butter flavored until college ....then it was a Tom Petty song.... last dance with may jane.....