Editing Uraninite

{{short description|Uranium-rich oxide mineral}}
{{redirect|Pitchblende}}
{{Infobox mineral
| name          = Uraninite
| category      = [[Oxide minerals]]
| boxwidth      =
| boxbgcolor    =
| image         = Pitchblende schlema-alberoda.JPG
| imagesize     = 260px
| caption       = Pitchblende from Niederschlema-Alberoda deposit, [[Germany]]
| formula       = [[Uranium dioxide]] or [[uranium(IV) oxide]] (UO<sub>2</sub>)
| IMAsymbol     = Urn<ref>{{Cite journal |last=Warr |first=L.N. |title=IMA–CNMNC approved mineral symbols |journal=Mineralogical Magazine |volume=85 |issue=3 |pages=291–320 |date=2021 |bibcode=2021MinM...85..291W |s2cid=235729616 |doi=10.1180/mgm.2021.43 |doi-access=free}}</ref>
| molweight     =
| strunz        = 4.DL.05
| system        = [[Cubic (crystal system)|Isometric]]
| class         = Hexoctahedral (m{{overline|3}}m) <br/>[[H-M symbol]]: (4/m {{overline|3}} 2/m)
| symmetry      = ''Fm{{overline|3}}m''
| unit cell     = a = 5.4682&nbsp;Å; Z&nbsp;=&nbsp;4
| color         = Steel-black to velvet-black, brownish black, pale gray to pale green; in transmitted light, pale green, pale yellow to deep brown and green-gray (thin fragments)
| habit         = Massive, [[botryoidal]], granular. Octahedral crystals uncommon.
| twinning      =
| cleavage      = Indistinct
| fracture      = Conchoidal to uneven
| mohs          = 5–6
| luster        = Submetallic, greasy, dull
| refractive    =
| opticalprop   = Isotropic
| birefringence =
| pleochroism   =
| streak        = Brownish black, gray, olive-green
| gravity       = 10.63–10.95; decreases on oxidation
| density       =
| melt          =
| fusibility    =
| diagnostic    =
| solubility    =
| diaphaneity   = Opaque; transparent in thin fragments
| other         = [[Image:Radioactive.svg|25px]] [[Radioactive]] 70 [[Becquerel|Bq/g]] to 150 kBq/g
| references    = <ref name=Klein>Klein, Cornelis and Cornelius S. Hurlbut, Jr., ''Manual of Mineralogy'', Wiley, 1985, 20th ed. pp. 307–308 {{ISBN|0-471-80580-7}}</ref><ref name=HBM>{{cite book |editor1=Anthony, John W. |editor2=Bideaux, Richard A. |editor3=Bladh, Kenneth W. |editor4=Nichols, Monte C. |title=Handbook of Mineralogy |publisher=Mineralogical Society of America |location=Chantilly, VA |url=http://rruff.geo.arizona.edu/doclib/hom/uraninite.pdf |chapter=Uraninite |access-date=December 5, 2011 |isbn=0-9622097-2-4 |volume=III (Halides, Hydroxides, Oxides) |archive-url=https://web.archive.org/web/20120314011324/http://rruff.geo.arizona.edu/doclib/hom/uraninite.pdf |archive-date=March 14, 2012 |url-status=live}}</ref><ref name=Mindat>[http://www.mindat.org/show.php?id=4102 Uraninite] {{webarchive |url=https://web.archive.org/web/20121110071006/http://www.mindat.org/show.php?id=4102 |date=November 10, 2012}}. Mindat.org</ref><ref name=Webmin>[http://webmineral.com/data/Uraninite.shtml Uraninite] {{webarchive |url=https://web.archive.org/web/20111021115239/http://webmineral.com/data/Uraninite.shtml |date=October 21, 2011}}. Webmineral.com</ref>
| var1 = Pitchblende 
| var1text = Massive
}}

'''Uraninite''', also known as '''pitchblende''', is a [[Radioactive decay|radioactive]], [[uranium]]-rich [[mineral]] and [[ore]] with a [[chemical composition]] that is largely [[Uranium dioxide|UO<sub>2</sub>]] but because of [[oxidation]] typically contains variable proportions of [[Triuranium octoxide|U<sub>3</sub>O<sub>8</sub>]]. [[Radioactive decay]] of the uranium causes the mineral to contain [[oxide]]s of [[lead]] and trace amounts of [[helium]]. It may also contain [[thorium]] and [[rare-earth elements]].<ref name=Klein/><ref name=Mindat/>

==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]].

==Occurrence==
[[File:Uraninite-usa32abg.jpg|thumb|left|Uraninite crystals from [[Topsham, Maine]] (size: 2.7&nbsp;×&nbsp;2.4&nbsp;×&nbsp;1.4 cm)]]
Uraninite is a major ore of uranium. Some of the highest-grade uranium ores in the world were found in the [[Shinkolobwe]] mine in the [[Democratic Republic of the Congo]] (the initial source for the [[Manhattan Project]]) and in the [[Athabasca Basin]] in northern [[Saskatchewan]], Canada. Another important source of pitchblende is at [[Great Bear Lake]] in the [[Northwest Territories]] of Canada, where it is found in large quantities associated with [[silver]]. It also occurs in [[Australia]], the [[Czech Republic]], [[Germany]], [[England]], [[Rwanda]], [[Namibia]] and [[South Africa]]. In the United States, it can be found in the states of [[Arizona]], [[Colorado]], [[Connecticut]], [[Maine]], [[New Hampshire]], [[New Mexico]], [[North Carolina]] and [[Wyoming]]. The geologist [[Charles Steen]] made a fortune on the production of uraninite in his Mi Vida mine in [[Moab, Utah]]. Uranium ores from the [[Ore Mountains]] (today the border between the Czech Republic and Germany) were an important supply of both the wartime [[German nuclear program]] (which failed to produce a bomb) and the [[Soviet nuclear program]]. Mining for uranium in the Ore Mountains (under the auspices of [[SDAG Wismut]] after the war) ceased after the collapse of the [[German Democratic Republic]].

Uranium ore is generally processed close to the mine into [[yellowcake]], which is an intermediate step in the processing of uranium.
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==See also==
* [[List of minerals]]
* [[List of uranium mines]]
* [[Thorianite]]
* [[Uranium ore deposits]]

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==References==
{{reflist}}

== External links ==
* {{Commons category inline|Uraninite}}

{{Ores}}

[[Category:Cubic minerals]]
[[Category:Minerals in space group 225]]
[[Category:Oxide minerals]]
[[Category:Radioactive minerals]]
[[Category:Uranium(IV) minerals]]
[[Category:Blendes]]