metal detecting i found a piece that looks like a civil war breast plate but it has a heart on it what is it?

It’s worth having a civil war expert take a look at it. I would contact your nearest university and get a historian to initially look it over and see if it is genuine and potentially rare or valuable. The historian can help you a great deal even if they cannot assure authencity. As for its value, authenticity is paramount, which is why I suggest the university first. If authenicated, you can take to a specialist to have it valued.

Holiday Metal Detecting Finds