Jáchymov (yäˈkhĭmôf) [key], Ger. Joachimsthal, town, NW Czech Republic, in Bohemia, in the Erzgebirge [ore mountains]. The productivity of its uranium mines, once extensive, has declined since World War II. It is also a noted health resort, with thermal radioactive springs. Jáchymov was the main center of silver mining in Europe after the 16th cent., but its present output is negligible. The word Thaler, from which dollar is derived, is an abbreviation of Joachimsthaler, the name of a coin first struck there in the 16th cent.