Hi there,
Yup that is a quarter blank(also known as a blank Planchet), you can tell by the raised rim. If you have a small digital scale you can weight it to see if it is genuine, it should be 5.67 grams. It not not worn blank because the rim would not be as present if the coin was completely worn blank. I have found several penny blanks, never a quarter.
Let us know how much she weighs....I found what I think is a Half blank planchet, it looks good, but it only weighs 11.2 grams, I'm thinking someone may have ground it down