Dime Without Reeding

Probably post-mint damage ( PMD). Someone could have rolled it under a metal bar to flatten it out. Are you sure the diameter is precisely the same as a normal dime, or is it slightly smaller?

A less likely possibility is that it was dropped into a slot machine thousands of times, but coin-operated slot machined aren't common these days. This would have worn the edge down. If it received this wear from a slot machine, the face of the coin should be very nicked up with contact marks.

if you can post a picture of both faces and the edge it would help tremendously

I agree that it's PMD. The edge looks 'brassy' because the core of the dime, as well as the quarter and half, is pure copper (even the outer layers are three-quarters copper).