All other isotopes of aluminium are radioactive. Quite possibly the most stable of such is 26Al, having a 50 %-life of 717,000 yrs: when it was present together with steady 27Al from the interstellar medium from which the Photo voltaic Process shaped (feel to have already been produced by stellar nucleosynthesis https://donovanhxman.nizarblog.com/37807569/5-simple-techniques-for-sheds-and-garages