Did you know that the critical metal tantalum was discovered in a mineral from a feldspar mine in Sweden?

Tantalum is used in the high-efficiency capacitors found in a wide range of electronics including mobile phones as well as in many extremely durable alloys.

The Swedish chemist Anders Gustaf Ekeberg discovered a strange mineral among others from the Ytterby pegmatite mine near Waxholm, north of Stockholm, in the late 1790s. This mineral, later called yttrotantalite, contained a supposedly new metal and Ekeberg published his discovery of the new metal, named tantal (tantalum) in 1802.

The image shows a c. 2m high section of the wall in the Ytterby granitic pegmatite quarry, north of Stockholm, Sweden. Together with coarse white quartz and white-pale grey feldspar are large, platy black crystals of the mica mineral biotite (up to 1m wide, but very thin), on which small crystals of several niobium-tantalum minerals occur. Photo: Erik Jonsson/SGU.

Ytterby was already by that time famous for the discovery of what was to become yttrium and the first of the rare earth elements (REE), after the 1794 publication on the new metal “yttria”. Later, the name of Ytterby would be immortalised by no less than four rare earth metals named after this little village with its pegmatite mine; yttrium (Y), ytterbium (Yb), terbium (Tb) and erbium (Er). Despite the local abundance of rare metal minerals in the Ytterby granitic pegmatite, it was only mined for the industrial minerals quartz and feldspar.

The FRAME project is, among other things, doing a survey of the pan-European  distribution of the this critical metal.