Isotopes of Gold

There is one stable isotope of gold, and 18 radioisotopes with 195Au being the most stable with a half-life of 186 days.

Gold has been proposed as a "salting" material for nuclear weapons (cobalt is another, better-known salting material). A jacket of natural gold, irradiated by the intense high-energy neutron flux from an exploding thermonuclear weapon, would transmute into the radioactive isotope Au-198 with a half-life of 2.697 days and produce approximately .411 MeV of gamma radiation, significantly increasing the radioactivity of the weapon's fallout for several days. Such a weapon is not known to have ever been built, tested, or used.