1955 DD Obv

John1

The others have it correct, but I should add that this is not a doubled die at all. To illustrate it in a way that would make more sense, this particular die was completely normal when it was hung on the press to start minting coins. The first 100,000 or more coins minted with this die looked like any other. At some point, the edges of the die started to turn brittle and chipped out one small piece at a time. The result is the coin you have.

In contrast, any one of the three known doubled die obverses for 1955 were doubled when they were first hung on the press to start making coins. Every single coin the die made had the doubling on it because the actual design on the die was doubled from the start. That's a doubled die...and the difference between a doubled die and what you have there.