I found this Quarter in my change and noticed it because the lip seemed to be deeper than a normal coin. Upon closer inspection I noticed that the top rim seemed to be doubled. If you could tell me exactly what it is that would be great.
I understand (and I am not an expert) that the force required to create a coin out of metal is quite substantial and sometimes the whole machine shudders or after the strike it sort of hiccups and then you get that appearance of doubling.
The doubling you refer to on the rim is call finning. A coin is struck from 3 dies. The hammer and anvil dies strike the obverse and reverse. Then there is also the collar which forms the edge of the coin. In the case of this quarter it forms the reeded edge. There is a small gap between the die and the collar and some metal can flow between them. So what you see is the inner part of the rim is the edge of the die and the outter part is the metal that flowed up between the dies. This is very common and is not considered an error unless the finned edge is very high.