[attachmentid=2047] I haven't seen this type of toning before, it's only on the obverse.
Ron

Seems like some kind of chemical reaction - seems like bubble-like isn't it? And if the surface is only exposed to this and oxidized, it is a good reason why the reverse isn't anything like this.

This came out of a bag of 1972 cents, there is another one similar to this and the rest are fine.

almost looks like gator skin, I have no clue

My theory would be that it’s had some kind of bubbly liquid on it. Once the bubbles were burst the liquid left behind might leave such a stain.

It could have been pre minting as well, say they cleaned a sheet of copper to have planchets punched from, and didn't have it completely dry?

You know that if you break a thermometer with mecury in it the droplets will form little balls

This looks like a liquid that tried to retract in perfect circles but failed leaving irregular stains
when dry
I guess it is one of the liquids used in the preparation of blanks which did not get washed off
maybe because two blanks stuck together

A better question, did you get an DDO's out of the bag?

Looks kinda fishy

So the other day I was looking through some rolls and came across a bunch of 72's. No dice but on coppercoins.com they list a ton of varieties besides the big DDO. My eyes were hurtin' after

eyepain. I know how you feel... my back was hurtin the other day also from lookin through a bunch of pennies

I knew this hobby was dangerous!

Did you know that the guy that runs that coppercoins forum web site has 2 books out on just Lincoln Cents? They are called Looking Through Lincoln Cents. He sells them on his web site I think but I bought both editions at coin shows. Also, if you had bought that remake of the first edition of the Red Book recently offered you would have noticed at the rear was a few drawings from the same person. You may want to go to his web site and ask him about that coin. He has taken virtually thousands of photos of coins and knows Lincolns really well.