What Is Going On With This 1988-D Roosevelt Dime?

That actually looks like a partially missing clad layer. The clear lack of cladding, sharp details near the break, and low pressure in the middle are all promising signs.

I look forward to hearing from the experts.

MisterT, the reverse looks like that since the planchet was too thin there to achieve the striking pressure necessary. Another good reason to think the clad layer split off after rolling but before striking.
On further examination, it looks like another section (7:00-8:00) is on the verge of separating too.

Arnbrhm, can you tell us the weight?

Wonderful find.

Bingo. If it split after strike, the reverse would look normal and the obverse portion would be striated and otherwise featureless. You can tell the copper was the surface exposed to the die since the design elements are struck on it.




There's no fill or Cud. Since that part of the clad layer was missing, the planchet is thinner in that area. That means there's less metal available to fill the die, i.e. the pressure is low, so the devices don't get struck up. It's basically the same reason that the side opposite a large Cud is weakly struck; the pressure is too low there since the same amount of metal is trying to fill a much larger space between the dies.

Numisma, thank you for the explanation and education. I would have totally mislabeled that reverse as filled die and a Cud.

Thanks everyone for the feedback!

Numisma, the weight came out to 2.213g

To the left of the motto, it appears the cladding is struck on to that area, still attached. So possibly this coin will be normal in weight, or close to normal? Interesting.

At first glance it looked like glue, but you can usually see through glue.