Aluminum, which is so cheap now that it is used to make cans and cooking utensils, wasonce more valuable than gold. At a banquet, the Emperor of France, Napoleon III, gave his most honored guests aluminum cutlery, while everybody else had to make do with silver. Aluminum bars were exhibited alongside the French crown jewels at 1855's Exposition Universelle and the pyramid set atop the Washington Monument is made of 100 pure ounces of the metal.
Aluminum was valuable because it was exceedingly difficult to extract from ore, but in 1886, with invention of the Hall-Héroult process, its supply exploded...