High Quality Content by WIKIPEDIA articles! Uraninite is a radioactive, uranium-rich mineral and ore with a chemical composition that is largely UO2, but also contains UO3 and oxides of lead, thorium, and rare earth elements. It is most commonly known as pitchblende (from pitch, because of its black color, and blende, a term used by German miners to denote minerals whose density suggested metal content, but whose exploitation was, at the time they were named, either impossible or not economically feasible). The mineral has been known at least since the 15th century from silver mines in the Erzgebirge Mountains, Germany. However, the type locality is Jachymov in the Czech Republic, from where F.E.Bruckmann described the mineral in 1727. Pitchblende from the Johanngeorgenstadt deposit in Germany was used by M. Klaproth in 1789 to discover the element uranium. Данное издание представляет собой компиляцию сведений, находящихся в свободном доступе в среде Интернет в целом, и в...