Cobalt

• 1. Introduction

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  Cobalt sits at atomic number 27 on the periodic table, but its story begins not in a laboratory, but in a German silver mine where frustrated miners blamed a goblin for their troubles. Sixteenth-century German miners called a troublesome blue-tinted ore "kobold ore" - goblin ore - because it refused to yield silver or copper, and when they tried to smelt it, the ore released poisonous arsenic fumes. For generations, the color those ores produced was assumed to come from bismuth. Nobody suspected that something entirely new was hiding inside.

  Then in 1735, Swedish chemist Georg Brandt changed the picture entirely. He showed that this notorious ore contained a previously unknown element. Cobalt became the first metal discovered since ancient times. Every metal known before it - iron, copper, silver, gold, zinc, mercury, tin, lead, and bismuth - had no recorded discoverer. Cobalt broke that streak.

  Today cobalt is woven into the infrastructure of modern life: the blue pigment in ancient Egyptian jewelry, the cathodes in the battery powering your phone, the alloys in jet turbine blades, and a treatment used in cancer radiotherapy. Yet most of the world's supply comes from a single country, mined under conditions that have drawn lawsuits, international investigations, and a reckoning from Apple, Tesla, and some of the largest technology companies on earth. How a goblin's ore became one of the most contested materials of the 21st century is the thread this documentary follows.

• 2. The Name and Its Demons

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  Georgius Agricola, the 16th-century authority on mining and mineralogy, wrote about both the troublesome kobelt ore and the mine spirits called "kobel" that miners blamed for underground misfortune, but he never connected the two. That connection came from a contemporary who suggested the ore was blamed on the spirit, and the linguistic link was formalized much later by a late 18th-century writer who argued the word "cobalt" formed from the spirit's name.

  Grimms' dictionary, published in 1868, weighed in with its own account. It described the kobalt ore as blamed on a mountain spirit held responsible for stealing silver and leaving behind an ore that caused poor air quality and other health hazards underground. The dictionary equated the word "kobel" with "kobold", treating it as a household spirit rather than a mine demon.

  The etymological debate did not stop there. Paul Kretschmer, writing in 1928, argued that the "house ruler" meaning was the original and proper one, and that the later association with mine demons was a corruption. The current edition of the Etymologisches Worterbuch, the 25th edition published in 2012, lists the household-spirit etymology under "kobold" while still maintaining under "kobalt" that the ore may have taken its name from a mine spirit or daemon metallicus.

  Alternative theories have also been proposed that involve no spirit at all. Karl Muller-Fraureuth suggested the word came from a bucket used in mining, frequently mentioned by Agricola, called the kobel or kobel. Another theory traces it to the Greek word cobathia, meaning arsenic sulfide, which produced the noxious fumes miners dreaded. An etymology from Slavonic kowalti was proposed by Emanuel Merck in 1902. Whether goblin, bucket, or poison gas gave cobalt its name, the dispute itself reveals how dangerous and baffling the ore was to the people who first encountered it.

• 3. Blue Across the Ages

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  An ingot of blue glass recovered from the Uluburun shipwreck, cast during the 14th century BC, stands as one of the earliest physical traces of cobalt in use. The oldest cobalt-colored glass yet identified comes from the eighteenth dynasty of Egypt, dated to between 1550 and 1292 BC. The Egyptians sourced the cobalt they needed from cobaltiferous alums found in their Western Oases.

  Cobalt-based blue pigments turn up across the ancient and medieval world with remarkable persistence. Researchers have detected cobalt in Egyptian sculpture, in Persian jewelry from the third millennium BC, in the ruins of Pompeii destroyed in 79 AD, and in Chinese artifacts from the Tang dynasty between 618 and 907 AD and the Ming dynasty between 1368 and 1644 AD.

  In 1780, Sven Rinman discovered cobalt green. In 1802 Louis Jacques Thenard discovered cobalt blue, the pigment now formally identified as cobalt aluminate. Before the 19th century, cobalt's primary role was as a pigment, used to make smalt - a blue-colored glass ground into powder for use in ceramics and painting. Smalt is produced by melting roasted mineral smaltite together with quartz and potassium carbonate to yield a dark blue silicate glass.

  During the 19th century a significant share of the world's cobalt blue and smalt production was carried out at the Norwegian Blaafarvevaerket. The first mines producing smalt in the 16th century were spread across Norway, Sweden, Saxony and Hungary. The discovery of cobalt ore in New Caledonia in 1864 began a shift that eventually pulled the center of production away from Europe entirely, a pattern of geographic disruption that would repeat with even larger consequences in the 20th century.

• 4. The Congo's Grip

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  In February 2018, asset management firm AllianceBernstein described the Democratic Republic of the Congo as economically "the Saudi Arabia of the electric vehicle age". The comparison was apt in both reach and consequence. The DRC currently produces approximately 75 percent of the world's cobalt supply, a concentration with few parallels in any critical material.

  The Mukondo Mountain project in Katanga Province, operated by the Central African Mining and Exploration Company, may hold the richest cobalt reserve in the world. It produced an estimated one-third of total global cobalt output in 2008. In July 2009, the company announced a long-term agreement to deliver its entire annual production of cobalt concentrate from Mukondo Mountain to Zhejiang Galico Cobalt and Nickel Materials of China.

  Glencore's Mutanda Mine shipped 24,500 tons of cobalt in 2016, which represented approximately 40 percent of Congo's output and nearly a quarter of global production. After a period of oversupply, Glencore closed Mutanda for two years in late 2019.

  On the 9th of March 2018, President Joseph Kabila updated the country's mining code, increasing royalty charges and declaring cobalt and coltan strategic metals. In February 2025, the DRC implemented a four-month suspension of cobalt exports, citing an oversupply of cobalt and a price decline to its lowest level in 21 years. Within the DRC, the China Molybdenum Company dominates production, contributing roughly 40 percent of the world's cobalt output and having doubled output from two of its mines from 56,000 tonnes to 114,000 tonnes over a single year.

• 5. Labor, Children, and Liability

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  Artisanal mining supplied between 17 and 40 percent of DRC cobalt production as of 2016. Roughly 100,000 cobalt miners in the country used hand tools to dig hundreds of feet underground with little planning and few safety measures, according to workers, government officials, NGO representatives, and reporters who visited isolated mines.

  Child labor has been documented in cobalt mining from African artisanal mines. On the 3rd of March 2017, Apple Inc. stopped buying ore from suppliers, including Zhejiang Huayou Cobalt, that sourced from artisanal DRC mines, shifting to suppliers verified to meet its workplace standards. In 2023, Apple announced it would convert to using recycled cobalt by 2025.

  In December 2019, International Rights Advocates filed a landmark lawsuit against Apple, Tesla, Dell, Microsoft, and Google's parent company Alphabet, alleging they knowingly benefited from the use of young children in cobalt mining. In 2024, a court ruled that suppliers facilitated forced labor but found that the US technology companies were not liable because they do not operate as a shared enterprise with the suppliers and that the alleged injuries were not fairly traceable to any of the defendants' conduct.

  The price of cobalt metal reached a nine-year high in October 2017, exceeding 30 US dollars a pound, up from roughly 10 dollars in late 2015, as technology companies seeking an ethical supply chain faced raw material shortages. After oversupply the price fell to around 15 dollars in 2019. A coalition of suppliers and customers formed the Fair Cobalt Alliance, whose members include Zhejiang Huayou Cobalt, Fairphone, Glencore, and Tesla, aiming to end child labor and improve working conditions in DRC mines.

• 6. Batteries and the Race to Reduce

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  Lithium cobalt oxide, known as LCO, was first sold commercially in 1991 by Sony and quickly became the standard cathode material for lithium-ion batteries. LCO batteries continue to dominate consumer electronics markets. Electric vehicles, however, began pulling in the opposite direction.

  From 2016 to 2020, the electric vehicle industry increased its demand for cobalt five-fold. Cobalt used specifically for electric vehicles grew 81 percent from the first half of 2018 to the first half of 2019, reaching 7,200 tonnes for a battery capacity of 46.3 GWh. Bloomberg New Energy Finance estimated that by 2030, global demand for cobalt could reach 47 times what it was in 2017.

  Battery makers responded by progressively reducing cobalt content in their cathodes. As of August 2020, cathode cobalt content had dropped from one-third in NMC 111 formulations to one-fifth in NMC 442 and then to one-tenth in NMC 811. Lithium iron phosphate batteries, which contain no cobalt, officially surpassed ternary cobalt batteries in installed capacity in 2021 with 52 percent of the market. Analysts estimated their share would exceed 60 percent in 2024. In September 2020, Tesla outlined plans to make its own cobalt-free battery cells entirely.

  The European Union also conducted research into the possibility of eliminating cobalt requirements from lithium-ion battery production altogether. Indonesia entered this picture sharply: starting from small amounts in 2021, Indonesian cobalt production grew from 1,300 tons to 20,500 tons between 2015 and 2024, with Benchmark Mineral Intelligence forecasting Indonesian output at 20 percent of global production by 2030.

• 7. Medicine, Poison, and Radiation

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  In 1938, John Livingood and Glenn T. Seaborg discovered the radioisotope cobalt-60. Within roughly two decades, cobalt-60 was being used at Columbia University to establish parity violation in radioactive beta decay, one of the foundational experiments in nuclear physics.

  Cobalt-60 produces gamma rays with energies of 1.17 and 1.33 MeV and has a radioactive half-life of 5.27 years. That steady, predictable decay made it valuable for external beam radiotherapy, sterilization of medical supplies, radiation treatment of food through cold pasteurization, industrial radiography to check weld integrity, and density measurements. The loss of potency over time requires periodic replacement of the cobalt source, which is one reason linear accelerators have largely replaced cobalt machines in modern radiation therapy.

  The same properties that make cobalt-60 useful also make it dangerous when mishandled. One of the worst radiation contamination accidents in North America occurred in 1984, when a discarded radiotherapy unit containing cobalt-60 was mistakenly disassembled in a junkyard in Juarez, Mexico.

  Cobalt's biological role is equally double-edged. Cobalt is the active center of cobalamins, the group of coenzymes known as Vitamin B12, essential to all animals. In the early 20th century, cattle on the North Island Volcanic Plateau of New Zealand suffered from what was called "bush sickness", traced to volcanic soils that lacked cobalt salts. A separate condition, "coast disease" of sheep in the Ninety Mile Desert of South Australia, also traced to cobalt deficiency in the 1930s. The solution developed for ruminants was "cobalt bullets" - dense pellets of cobalt oxide mixed with clay given orally. In 1966, however, the addition of cobalt compounds to stabilize beer foam in Canada produced a toxic form of cardiomyopathy that came to be known as beer drinker's cardiomyopathy, a reminder that the line between micronutrient and poison is narrower than it appears.