Swedish lieutenant Carl Axel Arrhenius discovered an asphalt-black mineral in the feldspar (a flesh-colored silicate) of the Ytterby mine. He immediately sent a sample to his friend, Johan Gadolin, a chemistry professor in Abo (now Turku, Finland), who named the mineral Yttria. It was later discovered that this mineral contained four new elements: the rare earth elements Yttrium, Erbium, Terbium, and Ytterbium. Per Cleve later separated Holmium (from Stockholm) and Thulium (from Thule) from the same mineral. Tantalum (a metal, not a rare earth) was discovered in another Ytterby mineral. Thus, the Ytterby mine became the source of seven chemical elements in a list that at the time numbered 70!
