Editing Uraninite (section)

==Overview==
Uraninite used to be known as pitchblende (from ''[[Pitch (resin)|pitch]]'', because of its black color, and ''blende'', from ''blenden'' meaning "to deceive", a term used by German miners to denote minerals whose density suggested metal content, but whose exploitation, at the time they were named, was either unknown or not economically feasible). The mineral has been known since at least the 15th century, from silver mines in the [[Ore Mountains]], on the German/Czech border. The [[Type locality (geology)|type locality]] is the historic mining and spa town known as Joachimsthal, the modern-day [[Jáchymov]], on the [[Czech Republic|Czech]] side of the mountains, where F. E. Brückmann described the mineral in 1772.<ref name=Mindat/><ref name="2003Veselovsky" >{{Cite journal |author=Veselovsky, F., Ondrus, P., Gabsová, A., Hlousek, J., Vlasimsky, P., Chernyshew, I. V. |title=Who was who in Jáchymov mineralogy II |url=http://www.jgeosci.org/content/JCGS2003_3-4__veselovsky1.pdf |archive-url=https://web.archive.org/web/20140423010012/http://www.jgeosci.org/content/JCGS2003_3-4__veselovsky1.pdf |archive-date=April 23, 2014 |url-status=live |journal=[[Journal of the Czech Geological Society]] |date=January 2003 |volume=48 |issue=3–4 |pages=193–205}}</ref> Pitchblende from the [[Johanngeorgenstadt]] deposit in Germany was used by [[Martin Heinrich Klaproth|M. Klaproth]] in 1789 to discover the element [[uranium]].<ref name="radiz">{{Cite journal |author=Schüttmann, W. |title=Das Erzgebirge und sein Uran |journal=RADIZ-Information |year=1998 |volume=16 |pages=13–34}}</ref>

All uraninite minerals contain a small amount of [[radium]] as a [[radioactive decay]] product of uranium. [[Marie Curie]] used pitchblende, processing tons of it herself, as the source material for her isolation of pure metallic radium in 1910.<ref>{{Cite web |title=Marie Curie and the Science of Radioactivity |url=http://history.aip.org/history/exhibits/curie/ |url-status=live |publisher=history.aip.org |access-date=June 29, 2017 |archive-url=https://web.archive.org/web/20170628203314/http://history.aip.org/history/exhibits/curie/ |archive-date=June 28, 2017}}</ref>

Uraninite also always contains small amounts of the [[Isotopes of lead|lead isotopes]] <sup>206</sup>Pb and <sup>207</sup>Pb, the end products of the decay series of the uranium isotopes <sup>238</sup>U and <sup>235</sup>U respectively. Small amounts of [[helium]] are also present in uraninite as a result of [[alpha decay]]. Helium was first found on Earth in [[cleveite]], an impure radioactive variety of uraninite, after having been discovered [[Spectroscopy|spectroscopically]] in the [[Sun#Atmosphere|Sun's atmosphere]]. The extremely rare elements [[technetium]] and [[promethium]] can be found in uraninite in very small quantities (about 200&nbsp;[[Kilogram#SI multiples|pg]]/kg and 4&nbsp;[[Femtogram|fg]]/kg respectively), produced by the [[spontaneous fission]] of [[uranium-238]]. Francium can also be found in uraninite at 1 [[francium]] atom for every 1 × 10<sup>18</sup> uranium atoms in the [[ore]] as a result from the decay of [[actinium]].