Editing Coffinite (section)

{{Short description|Uranium-bearing silicate mineral}}
{{Infobox mineral
| name        = Coffinite
| category    = [[Silicate minerals|Nesosilicate]]
| boxwidth    = 
| boxbgcolor  =#b46d4e 
| boxtextcolor = #fff
| image       = Blenda smolista + coffinit.jpg
| imagesize   = 260px
| alt         = 
| caption     = [[Uraninite|Pitchblende]] and coffinite in a sample from a Czech mine
| formula     = U(SiO<sub>4</sub>)<sub>1−x</sub>(OH)<sub>4x</sub>
| IMAsymbol=Cof<ref>{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|url=https://www.cambridge.org/core/journals/mineralogical-magazine/article/imacnmnc-approved-mineral-symbols/62311F45ED37831D78603C6E6B25EE0A|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}</ref>  
| molweight   = 
| strunz      = 9.AD.30
| dana        =
| system      = [[Tetragonal]]
| class       = Ditetragonal dipyramidal (4/mmm) <br/>[[H-M symbol]]: (4/m 2/m 2/m)
| symmetry    = ''I''4<sub>1</sub>/amd
| unit cell   = a = 6.97&nbsp;Å, c = 6.25&nbsp;Å; Z&nbsp;=&nbsp;4
| color       = Black (from organic inclusions; pale to dark brown in [[thin section]]
| colour      = 
| habit       = Rarely as crystals, commonly as colloform to botryoidal incrustations, fibrous, pulverulent masses
| twinning    = 
| cleavage    = 
| fracture    = Irregular to subconchoidal
| tenacity    = Brittle to friable
| mohs        = 5–6
| luster      = Dull to adamantine
| streak      = Grayish black
| diaphaneity = Opaque, transparent on thin edges
| gravity     = 5.1
| density     = 
| polish      = 
| opticalprop = Uniaxial (+/−)
| refractive  = n<sub>α</sub> = 1.730–1.750 n<sub>β</sub> = 1.730–1.750
| birefringence = δ = 1.730
| pleochroism = Moderate; pale yellow-brown parallel to and medium brown perpendicular to long axis
| 2V          = 
| dispersion  = 
| extinction  = 
| length fast/slow =
| fluorescence= 
| absorption  =
| melt        = 
| fusibility  = 
| diagnostic  = 
| solubility  = 
| other       = [[Image:Radioactive.svg|25px]] [[Radioactive]]
72.63% (U)
| alteration  = [[Metamict]]
| references  = <ref>[https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Coffinite Mineralienatlas]</ref><ref name=HBM>{{cite web |last1=Anthony |first1=John W. |last2=Bideaux |first2=Richard A. |last3=Bladh |first3=Kenneth W. |last4=Nichols |first4=Monte C. |title=Coffinite |url=http://www.handbookofmineralogy.org/pdfs/coffinite.pdf |website=Handbook of Mineralogy |publisher=Mineral Data Publishing |access-date=19 June 2022 |date=2005}}</ref><ref name=Webmin>[http://webmineral.com/data/Coffinite.shtml Webmineral data]</ref><ref name=Mindat>{{mindat|id=1106|title=Coffinite}}</ref><ref name=Stieff55>{{cite journal | last1 = Stieff | first1 = L.R. | last2 = Stern | first2 = T.W | last3 = Sherwood | first3 = A.M. | year = 1955 | title = Preliminary Description of Coffinite – A New Uranium Mineral | journal = Science | volume = 121 | issue = 3147 | pages = 608–609 | doi=10.1126/science.121.3147.608-a| bibcode = 1955Sci...121..608S | hdl = 2027/mdp.39015095016906 | hdl-access = free }}</ref><ref name=Fuchs58>{{cite journal | last1 = Fuchs | first1 = L.H. | last2 = Gebert | first2 = E. | year = 1958 | title = X-Ray Studies of Synthetic Coffinite, Thorite and Uranothorites | journal = American Mineralogist | volume = 43 | pages = 243–248 }}</ref><ref name=Stieff56>{{cite journal | last1 = Stieff | first1 = L.R. | last2 = Stern | first2 = T.W | last3 = Sherwood | first3 = A.M. | year = 1956 | title = Coffinite, a Uranous Silicate with Hydroxyl Substitution – A New Mineral | journal = American Mineralogist | volume = 41 | pages = 675–688 }}</ref><ref name=Hansley89>{{cite journal | last1 = Hansley | first1 = P.L. | last2 = Fitzpatrick | first2 = J.J. | year = 1989 | title = Compositional and Crystallographic Data on REE-Bearing Coffinite from the Grants Uranium Region, Northwestern New-Mexico | journal = American Mineralogist | volume = 74 | pages = 263–270 }}</ref><ref name=Moench62>{{cite journal | last1 = Moench | first1 = R.H. | year = 1962 | title = Properties and Paragenesis af Coffinite from Woodrow Mine, New Mexico | journal = American Mineralogist | volume = 47 | pages = 26–33 }}</ref><ref name=Min05>{{cite journal | last1 = Min | first1 = M.Z. | last2 = Fang | first2 = C.Q. | last3 = Fayek | first3 = M. | year = 2005 | title = Petrography and Genetic History of Coffinite and Uraninite from the Liueryiqi Granite-Hosted Uranium Deposit, SE China | journal = Ore Geology Reviews | volume = 26 | issue = 3–4 | pages = 187–197 | doi=10.1016/j.oregeorev.2004.10.006}}</ref><ref name=Zhang09>{{cite journal | last1 = Zhang | first1 = F. X. | last2 = Pointeau | first2 = V. | last3 = Shuller | first3 = L. C. |display-authors=et al | year = 2009 | title = Response of Synthetic Coffinite to Energetic Ion Beam Irradiation | journal = American Mineralogist | volume = 94 | pages = 916–920 | doi = 10.2138/am.2009.3111 | s2cid = 73581946 }}</ref><ref name=Hoekstra56>{{cite journal | last1 = Hoekstra | first1 = H.R. | last2 = Fuchs | first2 = L.H. | year = 1956 | title = Synthesis of Coffinite-USiO4 | journal = Science | volume = 123 | issue = 3186 | pages = 105 | doi=10.1126/science.123.3186.105| bibcode = 1956Sci...123..105H }}</ref><ref name=pnas15>{{cite journal|author1=Guo X. |author2=Szenknect S. |author3=Mesbah A. |author4=Labs S. |author5=Clavier N. |author6=Poinssot C. |author7=Ushakov S.V. |author8=Curtius H. |author9=Bosbach D. |author10=Rodney R.C. |author11=Burns P. |author12=Navrotsky A. |title= Thermodynamics of Formation of Coffinite, USiO4|journal= Proc. Natl. Acad. Sci. USA|year= 2015|volume= 112|issue= 21|pages= 6551–6555| doi= 10.1073/pnas.1507441112 |pmid=25964321 |pmc=4450415
|bibcode=2015PNAS..112.6551G |doi-access=free }}</ref>
}}
'''Coffinite''' is a [[uranium]]-bearing [[silicate mineral]] with formula: U(SiO<sub>4</sub>)<sub>1−x</sub>(OH)<sub>4x</sub>.

It occurs as black incrustations, dark to pale-brown in [[thin section]]. It has a grayish-black streak. It has a brittle to conchoidal [[fracture]]. The hardness of coffinite is between 5 and 6.

It was first described in 1954 for an occurrence at the La Sal No. 2 Mine, Beaver Mesa, [[Mesa County, Colorado]], US,<ref name=Mindat/> and named for American geologist [[Reuben Clare Coffin]] (1886–1972).<ref name=HBM/>
It has widespread global occurrence in [[Colorado Plateau]]-type [[uranium ore deposits]] of uranium and [[vanadium]]. It replaces organic matter in [[sandstone]] and in [[hydrothermal vein]] type deposits.<ref name=HBM/> It occurs in association with [[uraninite]], [[thorite]], [[pyrite]], [[marcasite]], [[roscoelite]], [[clay mineral]]s and [[amorphous]] [[organic matter]].<ref name=HBM/>