Aluminum is literally one of the most common elements on Earth. So why did aluminum cost more than gold at one time? The simple answer is that even though aluminum makes up about 8% of the Earth’s crust, it’s never been known to occur in its metallic form. Instead, aluminum appears mainly as a chemical compound, for example inside potassium aluminum sulfate.
Before aluminum was discovered, or even theorized, so called “alum compounds”, like potassium aluminum sulfate, were being used since antiquity for everything from leather tanning to fire-proofing. In fact, potassium aluminum sulfate is still used today in things like aftershave and baking powder.
You might think that these chemical compounds are referred to as “alum” because they contain aluminum, but this isn’t the case. The word “Alum” is the colloquial name given to a wide range of compounds that don’t necessarily include aluminum. The word aluminum itself is a derivative of the the word “alum”, not the other way around.
It’s usually thought that aluminum wasn’t theorized to exist until around 1807 when a chemist, Sir Humphrey Davy, argued that alum was the salt of a yet undiscovered metal, a metal Davy wanted to call “alumium”. But in 1778, the French chemist, Antoine Lavoisier, wrote in his book “Elements of Chemistry” that what he called “argilla” (aluminum oxide) could exist as a solid metal in theory, but that the technology of the day couldn’t separate the strongly bound oxygen atoms. In fact, argilla is tentatively listed as an actual element in Lavoisier’s original draft of his table of elements.
Aluminum as we know it today was first created in a lab by Hans Christian Oersted by heating aluminum chloride with potassium amalgam in 1825. In honor of Davy’s work which had inspired Oersted’s experiment in the first place, this new metal was dubbed “aluminum”. The flecks of metal that he produced using this method were so small and impure that a proper analysis of the metal was impossible.
Two years later, Friedrich Wöhler entered the aluminum manufacturing scene and developed a new way of isolating aluminum in its powdered form by improving upon Oersted’s original experiment. Even then it took another 18 years for enough of the metal to be produced for scientists to properly study its properties, and it wasn’t until 1845 that aluminum’s remarkable lightness was noted.
In 1854, Henri Sainte-Claire Deville developed a way of producing the metal on a much larger scale with the use of sodium, allowing kilograms of the metal to be produced at a time. For the sake of comparison, it had taken Wöhler years to produce the same amount of aluminum Deville could produce in a single day.
A year later, in 1855, 12 small ingots of aluminum were displayed at the “Exposition Universelle” a huge French exhibition organized at the behest of French emperor Napoleon III. Almost immediately after the exhibition, demand for this magical metal sky-rocketed. Its shininess combined with its almost ghostly lightness compared to other metals made it an ideal metal for jewelry and it wasn’t long until the French elite were wearing broaches and buttons made of aluminum.
Emperor Napoleon III granted Deville a virtually unlimited budget to study and produce the metal. Napoleon had hoped that this new metal could be used to produce lightweight weapons and armor for his army. Although a few helmets were produced, the sheer cost of refining the metal shelved the plan indefinitely.
Frustrated, Napoleon III had his supply of aluminum melted down and pressed into cutlery. As the story goes, Napoleon III was rumored to have eaten off of the aluminum plates while his guests had to make do with ones made of gold. Whether that story is true or not, at this point aluminum really was harder to get hold of than gold and the price reflected that, despite its prevalence in the Earth compared to gold.
All of that changed in 1886 when it was discovered that you could easily obtain oodles of aluminum using electrolysis. The discovery was made by Paul Lois Toussaint Héroult and Charles Martin Hall at almost the same time in both France and America, totally independent from one another. For this reason, the process, which is still used today, is referred to as the Héroult/Hall process in honor of both of them.
Two years after this, it was discovered by Karl Bayer that aluminum oxide could be made very cheaply from bauxite. As a result of both of these things, the price of aluminum plummeted by 80% overnight. In a few short years, aluminum went from being literally the most expensive metal on Earth to the cheapest. For reference, in 1852, before the Héroult/Hall process, aluminum sold for upwards of $1,200 per kilo. By the start of the 20th century, that same amount of aluminum cost under a dollar.