Army lieutenant and part-time chemist Carl Axel Arrhenius was excited when, in 1787, he came across a strange heavy black rock in an old quarry near the Swedish village of Ytterby.

Arrhenius named the newly discovered “earth” (the idea of elements had not yet been discovered) Yttrium after the town. As it would turn out, the mine in which Arrhenius discovered Yttrium would go on to reveal many more strange and exotic elements, such as Ytterbium, Terbium, and Erbium.

Thulium (“Thule” being a Latin name for the Nordic countries), Gadolinium, (named after Professor Johan Gadolin), Scandium, and Holmium (from the Latin name for Stockholm) were all derived from samples taken from the Ytterby Mine, making this the single richest source of elemental discoveries in the world.

The American Society for Metals has erected a plaque at the site.