was a new, unidentified earth element. Swedish chemist Anders Gustaf Ekeberg confirmed the discovery the following year and named it yttria, with the mineral named gadolinite. Many rare earth elements were discovered in the mineral gadolinite, which eventually proved to be the source of seven new elements that were named after the mineral ore and the area. These elements include yttrium (Y), erbium (Er), terbium (Tb), and ytterbium (Yb) and were first described in 1794, 1843, 1843, and 1878, respectively. In 1989 the ASM International society installed a plaque at the former entrance to the mine, commemorating the mine as a historical landmark. In addition, scandium (Sc) and three other lanthanides—holmium (Ho, named after Stockholm), thulium (Tm, named after Thule, a mythic analogue of Scandinavia), and gadolinium (Gd, after the chemist Johan Gadolin)—can trace their discovery to the same quarry. The European Chemical Society gave the Ytterby mine and the industrial complex of ABEA, Crete, Greece its Historical Landmarks Awards for 2018. See also Timeline of chemical element discoveries Geography of Stockholm References External links Blog entry on Ytterby YouTube tour of the mine site Location on Google Maps Google Earth view of Ytterby Web log — What do these elements have in common? Metropolitan Stockholm Populated places in Vaxholm Municipality Science and technology in Sweden Naming of chemical elements Feldspar mines in Sweden Quartz mines in Sweden