I believe that u have to change the cloudy mirror to the celestial mirror. u go to macalania woods and talk to a mother and her son near the save spot in macalania woods-south. The mom will tell u that she is supposed to meet her husband there. then go to the camp site in the woods to find her husband(he will be on the right). tell him where his wife and son are adn return to macalani woods-south. There will be a glowing path that wasnt there b4(first talk to the parents though). and then go up the glowing path and turn north until u see the boy. talk to him and use the cloudy mirror on a crystal that is behind him. the cloudy mirror will change into the celestial mirror. after that, u will be able to open those chests.
hope that was helpful cause it took me forever!