It is a struck through capped die dime. Nice find. An interesting thing about these is that the rim edge (where the outside edge of the die) is not sharp like a normal struck dime. The capped die is prevented from making this edge sharp because of the planchet covering the die. When they come off they something look like a saucer.

Other times they are removed. Other times they are continued to allow it to thin and fall off the die affect coins for a longer time.


Some deteriorate and rotate on the die:
