Incoming links: Ore
"Joachimsthal" is the German for it. Note how it is just near the modern frontier between Germany and the Czech Republic.
en.wikipedia.org/w/index.php?title=Uranium&oldid=1243907294#Pre-discovery_use:
In the early 19th century, the world's only known sources of uranium ore were these mines.
Apparently the region was a silver mining center:
Starting in the late Middle Ages, pitchblende was extracted from the Habsburg silver mines in Joachimsthal, Bohemia (now Jáchymov in the Czech Republic), and was used as a coloring agent in the local glassmaking industry
Ciro Santilli finds it interesting that radioactive decay basically kickstarted the domain of nuclear physics by essentially providing a natural particle accelerator from a chunk of radioactive element.
The discovery process was particularly interesting, including Henri Becquerel's luck while observing phosphorescence, and Marie Curie's observation that the uranium ore were more radioactive than pure uranium, and must therefore contain other even more radioactive substances, which lead to the discovery of polonium (half-life 138 days) and radium (half-life 1600 years).