Therefore, whoever maintains the monopoly on rare earths controls the world of high-tech, green technology and thus, in a certain way, the world itself. In the past, this control was in the hands of the United States, but today 97% of rare earths used around the world come from China. Unlike other metals, there are no mines or deposits of pure rare earth blocks. Rare earths are scattered among other metals and mixed together. To separate them from the other components, a series of processes are performed, producing often toxic and radioactive leftovers. It is no coincidence that the only US rare earth mine, in California, was shut down for a decade after a federal investigation showed that approximately two million litres of radioactive water had leaked into the ground. That is why it is easy to see that the extraction of rare earths is a complex business and, if done in an environmentally friendly way, not very profitable. This is why countries around the world currently prefer to buy their rare earth needs from China, where extraction is much cheaper but has devastating effects on the environment and on villagers near the mines [1]. If on one hand the world prefers to shift the responsibility for extraction to China, there is also a well-founded concern that the red dragon may impose increasingly onerous conditions (and possibly blackmail) on the world regarding the supply of rare earths. For this reason, new geopolitical strategies are emerging in an attempt to rebalance China’s overwhelming power. One example is the extraction of rare earths from the ocean floor, which the Japanese are among the pioneering countries [2]. This type of extraction, however, also has worrying consequences in terms of the environmental impact of the destruction of the seabed.

We may ask ourselves, what makes rare earths so special? What are, and where do their properties come from?
In order to answer these questions, let’s start by looking at the periodic table of elements. In it, each element is unique in the number of protons and electrons it contains. The elements are arranged in an ascending order of protons and electrons, so that each box contains an element with exactly one more proton and one more electron than the previous one, and one less proton and one less electron than the next one.
Nevertheless, there is a hole in the periodic table. After barium, which has 56 protons and 56 electrons, we jump straight to hafnium, with 72 protons and electrons. What are the fifteen missing elements? They are the lanthanides, shown separately – usually at the bottom of the periodic table – because of their peculiar electronic properties. Together with scandium and yttrium, they are the rare earths we are talking about.
They are shown separately due to the desire to maintain a certain order in the periodic table, which is dictated by the chemical characteristics of the elements. The rare earths’ peculiarity is that they possess electronic orbitals called “f”, which are different from those of the other elements. These orbitals are small, hidden by the remaining electronic cloud of the atom to which they belong. For this reason, they interact very little in chemical reactions, which are due to the outermost orbitals. Rare earths, therefore, differ from each other in the number of electrons within their small and protected “f” orbitals, while they all interact with other elements in a similar way through identical outer orbitals. This explains why it is so difficult to separate them from each other: as they all form equal bonds, it is very difficult to distinguish different types of rare earth atoms, and the process of recognition and separation is arduous.
But the peculiarities of “f” orbitals do not end here. The fact that they are protected and hidden by the outermost orbitals gives the electronic properties of rare earths greater stability. When two atoms are chemically bonded, they share the outermost electronic orbitals, resulting in their deformation. Furthermore, if we consider an atom with its electrons, the deformation of its outermost orbitals depends enormously on the material to which it binds. This means that different materials modify its original outermost orbitals differently. However, this is not the case with rare-earth “f” orbitals, which are protected by their outermost orbitals and are unaffected by bonds with other materials, thus allowing their electronic properties to remain unaltered.
In doing so, the optical and magnetic characteristics determined by the “f” orbitals remain quite stable within any composite material, making rare earths attractive for technological purposes. A striking example are quantum computers, which represent the latest frontier of modern technology. One way of building them is to use an electron’s different states as the different bits of a normal computer. It is obvious that an electron is a very unstable system, and the slightest disturbance can alter its state completely. This is why, thanks to the stability of their protected and hidden “f” orbitals, rare earths are potentially suitable for building new quantum computers [3].

From lighters to quantum computers, rare earths have made their way through technological progress and are becoming increasingly essential to humanity’s desire for growth. At this point, we can only hope to combine technological advancement with a new clean, sustainable and fair world. Yet, the logic we are pursuing bases the green and eco-sustainable conversion on unsustainable materials. A single wind turbine blade, for example, can contain hundreds of kilos of rare earths. At this rate, the risk is that, instead of disappearing, pollution will change shape and move from modern smart cities to remote and poor villages. By doing so, the conviction is that green society that are perpetuating the best for our planet, will land up forgetting whoever is outside the contemporary world.