1979 Dollar coin but it has a weird hump on it. any ideas what it is?

[okhunter]

Hi everyone, this is my first post I just started out metal detecting. I was detecting a old school site near my sister-in-laws house and she ask me to take a look at this dollar that she had gotten years ago. It has a hump on the back side side but no damage on the face side. The coin isn't bent but I don't see how it could be a misstrike. Any ideas would be helpful. The pictures didn't turn out that great.

thanks in advance
Danny

 

[DigginThePast]

Perhaps it was subjected to fire? Somewhere around I have a dime that I know was in a fire. It has a similar look with the hump and also has a lot of black staining.

 

[Jeffro]

Yep- fire damage.

 

[lonewolfe]

looks like the coins did that we used to shoot with BB guns

 

[Emperor Findus Cladius]

Fire damage. The intense heat caused a bubble to form inside the coin.

 

[Coins4Cheese]

I've heard of a striking error where the coin was struck, and an air bubble formed. So maybe it was that.