1983-D Cent Copper

Looks like zinc rot on the D. Might be a pillar sticking out of his chin?

The photos you posted don't look right at all. I have seen some of the other coins you have posted and they look much clearer than this one. Is there a reason you can't post any better photos?

I agree this is a zinc-based coin. The weight increase is from the zinc reacting with its environment, rotting. The zinc picks up particles from the air and binds with them, increasing in mass. Going stricly by weight this is a red herring indeed.

For the drop test, the tone doesn't differ too much, it's rather the length of it. If the tone is long and slowly tones out then it's copper, if it gets silenced almost instantly then it's zinc. The better way to listen to this is to balance the coin on the tip of your finger and touch it gently with a hard object, maybe another coin.

Give it a "heads or tails" flip. Zinc will let out a dull thud; copper will ring in the air. It really is impossible to mistake the two.

A 1983-D copper cent is an "early retirement" type of error coin. While not unknown, Denver was very diligent in clearing the copper planchets out of the machines *before* switching the the 1982 small date dies. It is very likely that the extremely few copper 1983-D cents were made intentionally by employees of the Mint. I do wish you the best of luck, but there is a 99.9999% chance this is just a normal '83-D.

If he doesn't update us, we will know if it was copper because it will be in all the coin magazines.