For a person, a mercury personality is someone who likes to talk, a chatterbox, a gossip, a tattle-tale. They are said to be good messengers because they like to share information but, for the very same reason, are not good at keeping secrets. They are very changeable and will jump from one fad to another, one love to another, one romance to another, one hobby to another. They like to read: books, letters, magazines, almost anything. They will probably be good as teachers, diplomats, writers, lobbyists, or any job that requires frequent public speaking or giving presentations. People who are too mercurial can counter that by wearing or carrying something made of iron or steel.