![\"Humboldtine\"](\"https:\/\/www.europesays.com\/uk\/wp-content\/uploads\/2025\/07\/SEI_259276267-941a.jpg\")
\n\t\tHumboldtine doesn\u2019t look like much, but these yellow lumps are highly prized (Picture: Pr\u00f6gler\/LfU)<\/p>\n
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\n\t\tHumboldtine doesn\u2019t look like much, but these yellow lumps are highly prized (Picture: Pr\u00f6gler\/LfU)<\/p>\n
When Roland Eichhorn popped open the dusty cardboard box, he couldn\u2019t believe it. <\/p>\n
There, in the basement of a stuffy government<\/a> office in Germany<\/a>, was a pile of six yellow lumps.<\/p>\n But these old rocks were one of the rarest minerals found on Earth<\/a>.<\/p>\n Until the discovery, only about a snowball-sized amount of the mineral, called humboldtine, had ever been found, Roland Eichhorn\u00a0of the Bavarian State Office for the Environment (LfU) said.<\/p>\n \u2018And we\u2019ve now found a second snowball,\u2019 he told the German newspaper Welt<\/a>. <\/p>\n Humboldtine, named after the naturalist Alexander von Humboldt, was first discovered in a rundown brown coal deposit in the Czech Republic in 1821.<\/p>\n \t\t The mineral is prized highly by collectors<\/a> because it has only been discovered in 30 locations across eight countries, including the UK. <\/p>\n \u2018We are legally obligated to make geological collection pieces accessible to the public,\u2019 Eichhorn\u00a0said.<\/p>\n Archivists were asked last year to digitise the agency\u2019s mineral and rock catalogue stored in the LfU basement in Hof, on the banks of the Saale, in 2023.<\/p>\n While scanning the shelves, a worker stumbled on a note written by a coal mine owner in 1949.<\/p>\n \u2018Humboldtine from the Mathias mine near Schwandorf,\u2019 it read, referring to an old open-pit mine for brown coal\u00a0by the river Naab.<\/p>\n Eichhorn\u00a0was taken aback, to say the least, not only because of how rare the mineral is, but because it wasn\u2019t listed anywhere in the collection.<\/p>\n \t\t The owner of the Mathias mine likely sent in samples of the rock, but it was never documented by agency officials. <\/p>\n Eichhorn\u2019s team immediately began rifling through more than 13,000 rocks collected across 250 years, only to discover the humboldtine stored anticlimactically in a drawer.<\/p>\n Inside was a box labelled \u2018Oxalit\u2019, German for organic mineral, with the rare material inside.<\/p>\n The dusty rock is the \u2018cyborg among minerals\u2019, Eichhorn\u00a0said.<\/p>\n Like all life on Earth, the mineral\u2019s crystal lattice contains carbon, water and oxygen, according to the mineral database Mindat<\/a>. But what sets it apart i the iron these ingredients to life are bound to.<\/p>\n Humboldtine only forms when iron-rich rocks contact specific acids in damp conditions, creating a lemon-yellow\u00a0clump that can contain crystals. Most of humboldtine unearthed so far are only millimetre\u2011sized grains.<\/p>\n \t\t But how these yellow-amber crumbs formed in the Mathias mine left Eichhorn baffled. <\/p>\n Brown coal, also called lignite, is one of the dirtiest fossil fuels and has a low concentration of carbon. <\/p>\n A brown coal mine isn\u2019t exactly the best conditions for humboldtine to form, yet LfU lab tests \u2018clearly confirmed\u2019 it was the precious crystal.<\/p>\n Digging at the mine had closed in 1966 and was flooded with water a few decades later. <\/p>\n Eichhorn said this makes it almost impossible for officials to investigate the site and obtain clues about where the humboldtine came from.<\/p>\n \u2018Why the yellow nodules formed in the Schwandorf brown coal will probably remain a\u00a0mystery<\/a>\u00a0forever,\u2019 the LfU said<\/a>.<\/p>\n Get in touch with our news team by emailing us at webnews@metro.co.uk<\/a>.<\/strong><\/strong><\/strong><\/p>\n For more stories like this, <\/strong>check our news page<\/strong><\/a>.<\/p>\n Arrow Arrow![\"Humboldtine](\"https:\/\/www.europesays.com\/uk\/wp-content\/uploads\/2025\/07\/SEI_259276275-723f.jpg\")
\n\t\tFewer than 30 samples of humboldtine, officially called FeC2O4.2H2O, have ever been discovered (Picture: Kemner\/LfU)<\/p>\n![\"Mathias](\"https:\/\/www.europesays.com\/uk\/wp-content\/uploads\/2025\/07\/SEI_259293517-4636.jpg\")
\n\t\tThe Mathias mine in Valbeck, Germany (Picture: Datawrapper\/Metro.co.uk)<\/p>\n![\"Humboldtine](\"https:\/\/www.europesays.com\/uk\/wp-content\/uploads\/2025\/07\/SEI_259276277-b413.jpg\")
\n\t\tHumboldtine (yellow) with halotrichite (white) under a microscope (Picture: Pr\u00f6gler\/LfU)<\/p>\n
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