It's hard to tell what made that happen. I think I'm inclined to go with @cpm9ball and say die deterioration.
That appears to be an extreme case of machine doubling. Die deterioration won't have the crisp shelf-like second image appearance, it would appear more as a bloated and distorted second image. If you look at the faded appearance of the leaves in the wreath above it, that is more what a deteriorated die would look like. The mintmark looks more like MDD.
That's not true, Jason. I've seen this kind of deterioration on Morgan dollars. It looks flat, but the shelf-like appearance is uneven, not following the straight line of the letter. Chris
So does that make this common silver Quarter worth more than its silver melt value or just nothing special
Physics-fan-pi makes a strong point about about MDD. But does that explain why the two "D"s have different sizes?
There's no way that was caused by the striking of the coin. The Ds are out of alignment, for one. Look at how they don't line up. How can those have come from a single D mint mark? Was that a magic mint mark that can strike in different sizes? I'm sorry, but I disagree with my esteemed colleagues. This isn't MD or MDD, and it doesn't take a PHD to figure that out.
Nor does it explain how, unlike machine doubling, the "second" D is thicker than the first. I think it's a partial fill from something relatively solid.
I wonder what the mint mark looked like originally. The coin shows considerable wear. That and some accumulation of foreign material makes cause just a conjection.
While this example appears to be more extreme than average, and I'm not sure of the cause, this type of anomaly is somewhat common on (at least later) silver Washington quarters. In past discussions it was referred to as "shearing" or "sheared", but I do believe this was more of a description of appearance as opposed to an accepted technical term.
