I'm pretty sure this is the most dramatic difference I've photographed between Obv & Rev of a coin....
"See a penny, pick it up, all day long, you'll have good luck!" JUST PICK IT UP SOONER, FOR GOD'S SAKE!
Looks like it was soaked in a very shallow pool of acid. Face up, with just enough solution to react with the reverse of the coin. You can see the fine pits on the reverse and not on the obverse. Wether or not the pitting was caused by a chemical soak or if they just exposed when the patina was removed we can’t say for sure, however based on the toughness of the reverse, I’d speculate that they were chemically induced. Edit - further examination reveals some pitting on the obverse rim. I’m guessing there’s more there that could be seen in a better light. With that, I’m going with some of the pitting was already present, however it appears the acid ‘enhanced’ them.
