I got this in some change a few weeks ago and it baffles me. One side is a 1979 quarter with no mint stamp and the other side looks to be a Canadian, UK or maybe Australian coin (Elizabeth II Dei Gratia Regina FD). The rim is half smooth and half riggid and it's the same thickness as a regular quarter. I've been hunting for information but haven't had any luck. Can anyone help me solve this mystery???
I assume you mean the edge is half smooth and half reeded. What you have is a coin that is made from two coins that have been planed down and glued or soldered together. It is nothing more than a trick coin and has no value other than as a curiosity. It is definitely NOT a Mint error. By the way, welcome to CoinTalk.