View source for Tantalite

{{Short description|Tantalum ore}}
{{confused|Tantalit|Tantalate}}
{{Infobox mineral
| name        = Tantalite
| boxwidth    =
| boxbgcolor  =
| image       = Tantalite.jpg
| imagesize   = 260px
| alt         =
| caption     = Tantalite, Pilbara district, Australia
| category    = [[Oxide minerals]]
| formula     = (Fe,Mn)Ta<sub>2</sub>O<sub>6</sub>
| IMAsymbol   = Ttl<ref>{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|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      = 4.DB.35
| dana        =
| system      = [[Orthorhombic]]
| class       = Dipyramidal (mmm) <br/>[[H-M symbol]]: (2/m 2/m 2/m)
| symmetry    = ''Pbcn'' (no. 60)
| unit cell   =
| color       = Dark black, iron-black to dark brown, reddish brown
| colour      =
| habit       =
| twinning    =
| cleavage    = Good in one direction
| fracture    = Subconchoidal
| tenacity    =
| mohs        = 6–6.5
| luster      = Submetallic to almost resinous
| streak      = Brownish-red to black
| diaphaneity =
| gravity     = 8.0+
| density     =
| polish      =
| opticalprop =
| refractive  =
| birefringence =
| pleochroism =
| 2V          =
| dispersion  =
| extinction  =
| length fast/slow =
| fluorescence =
| absorption  =
| melt        =
| fusibility  =
| diagnostic  =
| solubility  =
| impurities  =
| alteration  =
| other       =
| prop1       =
| prop1text   =
| references  = <ref>{{cite web|title=TANTALITE (Iron Manganese Tantalum Niobium Oxide)|url=http://www.galleries.com/Tantalite|publisher=Galleries.com|access-date=2011-10-25}}</ref><ref name=Mindat>[http://www.mindat.org/min-3882.html Tantalite]. Mindat.org (2011-09-07). Retrieved on 2011-10-30.</ref>
}}
The [[mineral]] group '''tantalite'''  [([[iron|Fe]], [[manganese|Mn]])[[Tantalum|Ta]]<sub>2</sub>[[oxygen|O]]<sub>6</sub>] is the primary source of the [[chemical element]] [[tantalum]], a [[corrosion]] (heat and [[acid]]) resistant metal. It is chemically similar to ''[[columbite]]'', and the two are often grouped together as a semi-singular mineral called [[coltan]] or "columbite-tantalite" in many mineral guides. However, tantalite has a much greater [[specific gravity]] than columbite (8.0+ compared to columbite's 5.2).<ref name=Mindat/> Iron-rich tantalite is the mineral tantalite-(Fe) or ''ferrotantalite'' and manganese-rich is tantalite-(Mn) or ''manganotantalite''.
Tantalite is also very close to ''[[tapiolite]]''. Those minerals have the same chemical composition, but different crystal symmetry: [[orthorhombic]] for tantalite and [[tetragonal]] for tapiolite.<ref>{{cite journal|author=P. Cerny|title=The tantalite-tapiolite gap: natural assemblages versus experimental data|journal= Canadian Mineralogist |volume=30 |year=1992|pages= 587|url=http://rruff.geo.arizona.edu/doclib/cm/vol30/CM30_587.pdf |display-authors=etal}}</ref>
Tantalite is black to brown in both color and streak. [[Manganese]]-rich tantalites can be brown and [[translucent]].
==Occurrence==
[[File:Manganotantalite.jpg|thumb|left|Manganotantalite from Alto do Giz, [[Rio Grande do Norte|RN]], [[Brazil]]]]
Tantalite occurs in granitic pegmatites that are rich in rare-elements, and in placer deposits derived from such rocks.<ref name="Conflict Coltan">{{cite journal|last1=Melcher|first1=Frank |display-authors=etal |title=Fingerprinting of conflict minerals: columbite-tantalite ("coltan") ores|journal=SGA News|date=June 2008|issue=23|page=1|url=https://www.researchgate.net/publication/228401189|access-date=10 August 2016}}</ref> It has been found in [[Australia]], [[Brazil]], [[Canada]], [[Colombia]] ([[Guainía Department|Guainía]] and [[Vichada Department|Vichada]]), [[Egypt]], northern [[Europe]], [[Madagascar]], [[Namibia]], [[Nigeria]], [[Rwanda]], [[The Democratic Republic of Congo]], the [[United States]] ([[California]], [[Colorado]], [[Maine]], and [[Virginia]]), and [[Zimbabwe]].  Brazil has the world's largest reserve of tantalite (52.1%).<ref name="USGS2006">{{cite web |publisher = US Geological Survey |last = Papp |first = John F. |title = 2006 Minerals Yearbook Nb & Ta |date = 2006|url = http://minerals.usgs.gov/minerals/pubs/commodity/niobium/#pubs |access-date = 2008-06-03}}</ref>
==Applications==
The tantalum metal extracted from tantalite is used in [[Alloy|alloys]] for strength and higher [[Melting point|melting points]], in [[glass]] to increase the [[Refractive index|index]] of [[refraction]], and in [[Surgery|surgical steel]], as it is non-reactive and non-irritating to body tissues. Much like glass, it is not suitable for use in [[hydrofluoric acid]] and strong hot [[alkali]] applications.<ref>[https://www.titanmf.com/alloys/applications-of-tantalum/ Titan Metal Fabricators. Alloys. Applications of Tantalum.] Retrieved on 2022-07-08.</ref>
==Sustainability==
The mining of tantalite causes many [[Environmental problems|environmental]] and social problems in the [[Democratic Republic of Congo]].<ref>[http://www.cellular-news.com/coltan/ Coltan, Gorillas and cellphones] {{Webarchive|url=https://web.archive.org/web/20050407083927/http://www.cellular-news.com/coltan/ |date=2005-04-07 }}. Cellular-news.com (2001-04-03). Retrieved on 2011-10-30.</ref><ref>[http://geology.about.com/od/conflictminerals/a/coltan.htm The Coltan Scandal]. Geology.about.com (2010-07-04). Retrieved on 2011-10-30.</ref>
==See also==
* [[Coltan mining and ethics]]
==References==
{{Reflist}}
==External links==
{{Commons category}}
* [http://webmineral.com/data/Tantalite-(Fe).shtml Webmineral Tantalite-(Fe)]
* [http://webmineral.com/data/Tantalite-(Mn).shtml Webmineral Tantalite-(Mn)]
* [http://rruff.geo.arizona.edu/doclib/hom/ferrotantalite.pdf Handbook of Mineralogy]
{{Manganese minerals}}
{{ores}}
{{Authority control}}
[[Category:Tantalum minerals]]
[[Category:Niobium minerals]]
[[Category:Manganese(II) minerals]]
[[Category:Radioactive gemstones]]
[[Category:Oxide minerals]]
[[Category:Orthorhombic minerals]]
[[Category:Minerals in space group 60]]