I have a 1972 d quarter that only weighs 3 grams is this a error coin and how much could it be worth?
Leave a coin in acid long enough and it will disappear. Damaged. They were probably trying to remove the clad layer to make it look like an error. Welcome to CT.
Yes. It is intentional damage. Not worth more then a Quarter. There are Mint Errors known as Struck on wrong stock. I own 2 Quarter that were struck on coin stock meant for Dimes. It's very rare to find those. Here are the 2 from my collection -