Kobold

The English word cobalt comes directly from German Kobalt, which is an altered form of Kobold — the goblin or household spirit of German folklore, a creature that inhabited mines and underground spaces. The Kobold was a complex figure in German belief: sometimes a helpful household sprite, sometimes a malicious trickster in mines who caused cave-ins, extinguished lamps, and led miners astray. When German miners in the Erzgebirge (Ore Mountains) of Saxony and Bohemia encountered a heavy bluish-grey metallic ore that resembled copper ore but produced no copper when smelted — instead releasing toxic fumes of arsenic trioxide and sulfur dioxide that poisoned workers and ruined the furnace charge — they blamed the Kobold. The ore was called Kobalt or Kobold-Erz (goblin ore), because it seemed to do what goblins did: pretend to be something useful and valuable while being secretly dangerous, tricking miners into wasted labor and harmed lungs. The name carried the accusation of supernatural deception.

The mineral that Germans called Kobalt ore had been used empirically for centuries before its metallic element was isolated. The intense blue color that cobalt compounds produce in glass and ceramics was exploited in ancient Egypt, China, and the Islamic world without knowledge of the metal involved. Smalt — powdered cobalt blue glass — was the standard blue pigment of Renaissance European painting, used by Vermeer, Raphael, and Titian. The vivid blue of Chinese porcelain, developed under the Tang dynasty (618–907 CE), came from cobalt oxide imported along the Silk Road from Persia. The Minoan frescoes of Santorini used cobalt blue. The color preceded the knowledge of the element by millennia; the goblin's accusatory name was given only when the ore proved recalcitrant and dangerous at the smelter, not when its beauty was first observed. Cobalt blue was used and valued for two thousand years before the metal behind it was named after a German mine-goblin.

The element cobalt was isolated and identified as a distinct metal by the Swedish chemist Georg Brandt in 1735–1739, making it the first metal to be discovered in the historical era — all previous metals (gold, silver, copper, iron, tin, lead, mercury) had been known since antiquity. Brandt's isolation of cobalt from the 'goblin ore' demonstrated that the blue color so long attributed to bismuth, copper, or magic was actually produced by a distinct metallic element. Brandt retained the German name, and 'cobalt' became the element's international designation. The naming of chemical elements after supernatural beings is unusual but not unprecedented: nickel, cobalt's close neighbor and fellow German mine-goblin (see below), has the same mythological naming origin. Both elements share the quality that originally earned them their goblin names — they were dangerous, deceptive ores that resisted the smelters' attempts to work them usefully.

Cobalt's modern importance extends far beyond its medieval reputation as goblin ore and Renaissance reputation as a blue pigment. Cobalt is essential to the chemistry of rechargeable lithium-ion batteries, where cobalt oxide forms the cathode material in the most energy-dense battery configurations. The smartphones, electric vehicles, and laptop computers of the twenty-first century depend on cobalt — most of it mined in the Democratic Republic of Congo under conditions that have attracted intense humanitarian scrutiny. The goblin ore of the Erzgebirge became the blue pigment of Renaissance painting and then the critical mineral of the digital economy, all without changing its German name. The Kobold of German mines, blamed for poisoning medieval smelters, now enables the battery technology that is supposed to save the planet from fossil fuels.