Uraninite named, was either unknown, impossible or not economically feasible). The mineral has been known at least since the 15th century from silver mines in the Ore Mountains, on the German/Czech border. The type locality is the historic mining and spa town known as Joachimsthal, the modern day Jáchymov, on the Czech side of the mountains, where F. E. Brückmann described the mineral in 1772. Pitchblende from the Johanngeorgenstadt deposit in Germany was used by M. Klaproth in 1789 to discover the element uranium. All uraninite minerals contain a small amount of radium as a radioactive decay product of uranium. Marie
Uranium mining in Colorado to about 1916. The uranium boom of the late 1940s revived the search for uranium orebodies in the gold and silver mines of the Front Range. Again, uranium was produced from a number of mines, but the orebodies were small and discontinuous. Pitchblende was discovered in 1948 in the Caribou silver mine at the town of Caribou, Boulder County. A small amount of uranium ore was produced. In 1949 janitor and weekend prospector Fred Schwartzwalder discovered uranium at an abandoned copper prospect in Jefferson County about ten miles northeast of Central City and eight miles north of Golden. The deposit