Similarly, the process for purifying aluminum is still the same as it was when it was first invented. Prior to the discovery of the Hall-Héroult processes in the mid 1800’s, (two men discovered the same process at the same time in different parts of the world,) pure aluminum was extremely rare. It used to be considered a fine metal, more expensive than silver or gold; Napoleon famously had aluminum silverware that he would use (instead of real silver) when he wanted to impress guests.