The color blue is one of the most difficult colors to obtain from nature, to the point that it has been guarded by an imp that it damaged the miners and it was called Kobold.
Despite its difficulty, blue has for centuries been a symbol of purity, even divine, as the cobalt blue stained glass windows of the church of Saint Denis, whose interior looks like heaven, as you can read in The church that radiates blue light.
In the sixteenth century, a new source of blue, European, increased the popularity of blue, when it was discovered that the silver mines of the mountains between Saxony and Bohemia, which had long been exploited, they were also rich in esmaltita.
The extraction of the new mineral, however, brought with it few inconveniences. Suddenly, a strenuous job, but also a continuous exposure to harmful emanations, which were spared when the other main ingredient of the mineral was cooked, the arsenic. Then, the miners began to attribute their afflictions to an earth imp called Kobold.
Abound in it Hugh Aldersey-Williams in The periodic table:
When Goethe's Faust first calls the figure of Mephistopheles, he successively invokes the "elemental four" of fire, air, water and earth, and the earth is personified by this evil spirit. (...) The Norwegian composer Edward Grieg called a brief pianistic scherzo of his, rumbling and aggressive, "Smatrold" (meaning little gnome); the Germans call the same piece "Kobold", but the chosen English translation, "Puck" (goblin, goblin), fails to cover the character's real malicious character.
Its chemical constitution was not fully known, and the element behind it had no proper name, but this did not prevent the blue pigment from becoming a highly appreciated item commercially.
Cobalt prospered anonymously for centuries before finally being discovered, around 1735, when Georg Brandt, a chemist and controller of the Swedish Mint, guessed that the esmaltita was not simply the compound of known and arsenic metals that had been assumed. He called the new metal cobalt and as a tribute to those unfortunate miners ... and perhaps also as a way to snatch this name from their pagan association and link instead to the shield of the science of the Enlightenment.