All other isotopes of aluminium are radioactive. By far the most secure of such is 26Al, using a fifty percent-lifetime of 717,000 several years: although it was present in addition to stable 27Al in the interstellar medium from which the Solar Method fashioned (believe that to are produced by stellar nucleosynthesis https://aluminium-greenhouse56778.techionblog.com/37521698/new-step-by-step-map-for-sheds-and-garages