Hans Christian Oersted discovered aluminum in 1825. Earlier scientists believed alum contained an unknown metal, but Oersted gets credit for the discovery because he was the first person to extract small amounts of aluminum from the compound.
The amount of aluminum extracted by Oersted was so small scientists could not determine the metal's properties. In 1827, chemist Friedrich Wohler developed a new aluminum extraction process, making it possible to produce larger pieces of the metal. Despite this advance, there was still a limited amount of aluminum available, making it an expensive process. In 1859, the price of aluminum dropped significantly, but $40 per kilogram was still too expensive for many people. Aluminum was not widely used until the early 1900s, when the supply finally caught up to the demand, resulting in a dramatic price decrease.