> In the Earth's crust, aluminium is the most abundant metallic element (8.23% by mass[68]) and the third most abundant of all elements (after oxygen and silicon).
TIL. I thought it would be relatively expensive due to the difficulty of extracting it.
The Washington Monument has an aluminum cap, which at the time was as expensive as silver. Two years later the Hall-Héroult process was invented, and as a result the price plummeted.
TIL. I thought it would be relatively expensive due to the difficulty of extracting it.
(Iron is much cheaper than I thought, too.)