Extremely Rare Mineral at the Munich Show

The Geological Service at the State Office for the Environment (LfU) is showcasing a true sensation at this year's Munich Show: the latest discovery of the rare mineral Humboldtin.
 
For over 50 years, the State Office for the Environment has been a loyal exhibitor at the Munich Show. One of the LfU’s tasks is to make geological collection pieces accessible to the public. During the digitization of the geo-archive, which holds stocks from 250 years, a real sensation was found: a very rare mineral called Humboldtin was discovered in a box.
 
The light-yellow mineral, named after the renowned naturalist Alexander von Humboldt, was discovered in February 2023. The team came across a letter from 1949 between the Brown Coal Mining Maxhütte A.G. – Mathias Mine near Schwandorf ("Mathiaszeche") and the Bavarian Geological State Office (GLA), discussing the presence of Humboldtin at the Mathiaszeche. Samples of Humboldtin had been handed over to the GLA, but they were not recorded in the catalogs.
 
Among 130,000 exhibits, two boxes containing small yellowish chunks were eventually found in one of the drawers. An old handwritten label identified the samples as "Humboldtin from the Mathiaszeche near Schwandorf." "Initially, we were skeptical whether it was really Humboldtin," said Georg Loth, Coordinator of the Central Geo-Archive and Head of the Rock Collection. "So far, only tiny crystals of Humboldtin have been found worldwide." Only about 30 locations are known, with two rhyolite quarries in the Spessart region in Bavaria. Analyses in the LfU’s rock laboratory in Marktredwitz confirmed it: It is Humboldtin, an organic compound of carbon, water, and iron.

Now, a new site for Humboldtin has been identified: Northwest of Schwandorf (Upper Palatinate), between Irlbach and Sitzenhof, there is a deposit of Tertiary brown coal. The recently discovered Humboldtin originates from this area. Brown coal was mined there from 1945 to 1966, and the area was later used as a landfill, making further finds impossible today.
 
The extraordinary find will be presented at the Munich Show – Mineralientage München at the State Office for the Environment's booth at the East Entrance. The experts from the LfU are looking forward to welcoming visitors and are happy to answer any questions.