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
Ida Noddack a predetermined result. According to Kenna and Kuroda technetium content expected in a typical pitchblende (50% uranium) is about 10 g/kg of ore. F. Habashi pointed out that uranium was never more than about 5% in Noddacks' columbite samples, and the amount of element 43 could not exceed 3 × 10 µg/kg of ore. Such a low quantity could not be weighed, nor give X-ray lines of element 43 clearly distinguishable from the background noise. The only way to detect its presence was to carry out radioactive measurements, a technique the Noddacks were not able to employ, but Segrè and