Nice condition for a 90 that came from crh but I'm guessing this is heat damage and not natural toning? I'm trying to decide if I want to keep it or not.
You have what is known as a Double Rim from the 3:00 to 7:00 position on the Obverse of your Dime If you see the reeding design inside the false rim then it's considered a Collar Clash.
I actually see a lot of those. I don't just check the rim when I crh, that feels....cheap, I guess. I look at every coins obverse and reverse. So that's a collar clash? I don't know much about that.