The only dried mint I can find is spearmint. Is this what I want? It doesn't seem right.

Hello! Typically Persian foods that call for dry mint refer to dried spearmint. Personally, my family and I dry our own peppermint for our food. So in my opinion there is no significant difference. You could always dry your own mint by laying the leaves on a cloth to dry for a couple of days then grinding them in a mortar and pestle or with your hands.

I think spearmint is right. Fresh spearmint is generic ‘mint’ in recipes if peppermint isn’t specified (usually for a dessert).