When Samuel Borkson and Arturo Sandoval III, the artists behind the cheerful collective FriendsWithYou, created Psychic Stones, a series of mystic healing crystals, they sought to maintain the sense of magic that characterizes the rest of their portfolio. (The duo is perhaps best known for their colorful, large-scale installations.) And so, each amulet carries a unique, customized spell— “Evil Expel,” for example, and “Happiness.” Rock on.