This coin is very shiny and there is something on the reverse. Was this coin dipped or altered in some way?
Can't tell exactly what it is, but it's not an error. What's there was 'put on' the coin after it was in circulation. Looks like a 'blob', but can't tell what it is for sure from that photo.
the "blob" looks like metal which is broken at the top, so maybe someone once made it into a tie clasp or cuff links...
The placement says to me that it was an earring. Pierced one, thats where the stud was soldered on and with the location the dime would of been correct when placed on the ear.
possible earring. You learn something new every day. Just did a google on it ... wow, amazing ... https://www.google.com/search?q=dime earrings&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi-mumzx8jhAhVRKKwKHbD5B-4Q_AUIDygC&biw=1295&bih=618 Keep this in the back of your mind for a future "Mint Error" posting. and my one daughter had me damaging coins for her artsy hobby. I never thought of earrings. and there was a lot of cufflinks too https://www.google.com/search?biw=1...1..gws-wiz-img.......0i30j0i10i30.Vv_WM6VNMyo