Since I had to be in Madrid to watch the fantastic concert by the Wiener Sängerknaben, the plan had been to attend the yearly Expominerales mineral fair in the Mine and Energy Engineering School Escuela Técnica Superior de Ingenieros de Minas y Energía (ETSIME) that same day. However, the fair closes on Saturdays between 14:00 and 16:00 for a lunch break, so since the weather was so horrid, I decided not to wait. On Sunday, the weather forecast was slightly less miserable, and in the end I was lucky with only some gentle rain as I walked between the train station and the Engineering School, nothing like the sleet deluge the previous day.

Expominerales fills the ETSIME with stalls selling minerals, fossils and crystals offered by reputable sellers. Here I’ve seen the biggest megalodon teeth in my life, held a plesiosaur vertebra – which I regret not buying when I had the chance – and discovered that moldavite exists – and which I regret not buying when I had the chance… do you spot a pattern here? I did not break it anyway, because in the end I cannot afford most of what is sold, and I already own most of what I can…

I arrived at the School shortly after the exhibit opened around 10:00, and the area was still pretty empty. There were fewer stands than the previous years I’ve been there, and the moldavite stand was not there. Actually, there were very few meteorite-related stands this time around. I did see amazing modern-times frog fossils from Owens Lake. Owens Lake is called Patsiata in the Mono Native American language. In 1913, the lake dried out when the water from the Owens River was redirected and with years it has become a deadly salt flat, a source of alkali sand storms with a side of carcinogen materials. One of the minerals found in Owens Lake is trona, a crystal formed by the precipitation of sodium carbonate, making it a type of evaporite. In 2023, an atmospheric river caused floods in California, filling the lake up for the first time in over a century. The floods damaged infrastructure and created a surge of floodwater to the lake, which eroded surfaces and dragged a lot of small hibernating animals towards the lake, where they were killed instantly. Their soft tissues were quickly replaced by trona salt before the bodies even decomposed, creating a perfect cast of the poor critters. There were two on display at Expominerales and they were creepy!

Something else that caught my eye (and was actually within my doable price range) was a polished abalone shell. The Korean abalone (Haliotis discus) has been used for centuries in the art of najeonchilgi [나전칠기], which refers to decorating items with mother of pearl. The abalone can be polished in full, creating a whole iridescent body of nacre. These mollusks used to be collected by haenyeo [해녀], traditional female divers from the Jeju province, but most of them are farmed for food today. A small polished abalone came home with me.

The School opens its classic museum during the exhibit, and I always enjoy visiting it. However, after wandering around for a bit (and spending some money), I moved onto what basically is the next building over to the ETSIME, the Spanish Mining and Geology Institute IGME – Instituto Geológico y Minero de España, which hosts the Geomineral Museum Museo Geominero. The original design of the building was conceived by Francisco Javier de Luque, and work started in 1921. Though a congress was held there in 1925, construction went on until 1941. The building has not been extensively restored, but it presents deviations from the original plans, and even from subsequent ones.

The museum is hosted in the former hall, and to get there, first you have to go through a very bored security guard – who first asked if I was sure I wanted to be there. Once inside the building, one goes up the main staircase towards the gallery underneath a glass-and-iron skylight with the logo of the Mining Institute. It was designed by Luque himself and created by the Madrid workshop La Veneciana, a glassware shop dating from 1876 and which, under a different name, still exists today.

The museum is an open area, located underneath another incredible skylight. The displays are hosted in wooden cabinets in the main floor. The upper balconies can be accessed through spiral staircases and are protected by metalwork railings. One of the details I absolutely adore are the glassworks displaying geological sample cores of different surveys. I’ve never seen the library, but I was once part of a group which was allowed to play with some of the “lesser value” items they have as part of a training session, and that was super fun. The museum is probably one of my favourite spots in town.

From the architecture point of view, I like the building and the skylights. However, there are way more things to love in the museum, such as the wooden cabinets, full with samples of minerals, fossils and meteorites. The museum’s collection are divided into “Mineralogy and Petrology”, “Flora and Invertebrate fossils from Spain”, “Vertebrate fossils from Spain”, “Foreign fossils”, “Systematic invertebrate palaeontology”, “Micro-palaeontology”, “Fossil resin”, “Fossil tracks”, “Stromatolites”, and the “special exhibits”. One of these is a complete cavern bear (Ursus spelaeus), another one is an Ibex (Capra ibex). The last two have honour spots, with their own display.

When you come into the museum, one of the first things that you see, in front of the door, up on the first-floor balcony, is the cast of the most complete Tyrannosaurus rex skull ever found – Stan. Specimen BHI 3033, Stan, was found in 1987 and excavated in 1992, in South Dakota’s Hell Creek Formation. Stan lived around 65 million years ago, in the Cretaceous period. We know he fought for his life more than once – his ribs were broken and healed, two vertebrae were fused together, and he suffered a bite to his snout. Stan remains one of the most complete skeletons ever found, and probably the most-often cast. The skeleton made mainstream news when it was auctioned at Christie’s in New York due to money disputes among partners of the original owner-firm, Black Hills Institute. An anonymous buyer paid $31.8 million for it in October 2020. In 2022 it was disclosed that the Department of Culture and Tourism of Abu Dhabi had bought Stan for their projected new Natural History Museum.

On the ground floor there is a mastodon fossil Anancus arvernensis found in the 1990s. These animals related to modern elephants lived throughout the Miocene and went extinct in the Early Pliocene (two million years ago). The could have been around the size of a modern African bush elephants, but their tusks were mostly straight. They would have lived in steppe with dry and warm climate, but close to water. The fossilised bones were recovered are dated around 3.2 million years ago, and were dug from the Las Higueruelas site between 1948 and 1991.

After I wandered the museum for a while, I left towards my train which was delayed… 43 minutes. Fortunately, so were the ones that had to pass before, so I ended catching one in the right direction after only a twenty-minute wait. And then I got junk food, because some days have to end in junk food…