There is no such thing, it isn't a property like mass or an object. People have rabbits feet, four leaf clovers and such because it gives them the sense that they'll have "luck", but science has yet to prove that "luck" is anything but a fabrication.
Luck is a matter of being alert for opportunity. And seeing one, if it is ethical and honest, act on it. People who expect opportunities (good luck) see them coming. People who don't expect opportunities (bad luck) don't see them coming and don't act on them.