Two hundred years ago, no-one knew aluminium existed. Today it is everywhere – in cans, window frames, packaging, even car bodies. New uses for it are constantly being discovered – but it’s possible that one day we’ll be able to stop mining the ore, and rely completely on recycling.
Aluminium has a split personality.

It may look dull, but it is one of the most reactive metals in the periodic table.
“Aluminium fires are quite terrifying,” says Andrea Sella, chemistry professor at University College London.
“When you take aluminium and you burn it, you get a very, very intense fire.”
From that point of view, it may not be ideal for aircraft construction – but this disadvantage is outweighed by its strength, flexibility and exceptional lightness.

The soft, malleable metal’s alter ego is aluminium oxide, which forms a skin on the pure metal the moment it is exposed to air (and makes it unlikely that an aircraft will catch fire).

This oxide is so hard that it is used to make sandpaper and other abrasive materials.

Among gemstones, sapphires – crystals formed from the oxide – are second only to diamonds in their hardness.

Indeed, there is a growing industry for manufacturing industrial sapphires the size of a large bucket, suitable for use in bullet-proof glass, aeroplane windows and soon – unscratchable smartphone displays.

Although Aluminium is the third most abundant element in the earth’s crust, it was not isolated until 1825, and remained so scarce that it was valued more highly than silver for decades.

The reason it remained hidden for so long, unlike gold or silver, is that it is too reactive to occur in its pure form.

Instead it is found as bauxite, a reddish-brown ore named after the French town Les Baux, where it was first discovered.

Bauxite is found across the globe, and mining it is the easy part. Far trickier is extracting the metal. It was not until 1886 that a Frenchman and an American both cracked it.

You have to melt the bauxite in another mineral called cryolite, and then pass an electric current through it, separating the oxygen atoms from the aluminium. It takes four tonnes of bauxite to produce one tonne of aluminium.