Pearls: The Only Gem Made by a Wound

Every other gem is dug out of the earth. A pearl is the only one made by a living creature — and it starts as an injury. When something sharp slips inside an oyster's shell, the animal can't push it out. So it does something stranger: it wraps the irritation in thousands of layers of nacre, the same iridescent material as the inside of its shell, until the wound becomes the smoothest thing in the ocean. Queens were buried with them. Cleopatra allegedly drank one dissolved in vinegar to win a bet. And all of it started with something that hurt. If that's not the most beautiful secret in the jewelry box, we don't know what is.