{{Short description|Accessory oxide mineral found in granitic pegmatites}} {{Infobox mineral | name = Ixiolite | image = Ixiolite-490369.jpg | alt = | caption = Ixiolite found in Mozambique | category = Oxide minerals | formula = {{chem2|(Ta,Nb,Sn,Mn,Fe)4O8}}<ref name=Mindat/> or {{chem2|(Ta,Mn,Nb)O2}}<ref name=Mineralienatlas/> | IMAsymbol = Ix<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> | strunz = 4.DB.25 | dana = | system = Orthorhombic, some varieties might be monoclinic<ref name=Wise/><ref name=Mindat/> | class = Dipyramidal (mmm) <br/>H-M symbol: (2/m 2/m 2/m) | symmetry = ''Pbcn''<ref name=Mineralienatlas/> | unit cell = a = 4.785, b = 5.758 <br/>c = 5.16 [Å]; Z = 4<ref name=Mineralienatlas/> | color = Steel-grey, black | colour = | habit = Irregular granular or inclusions, also as prismatic crystals; some varieties might be pseudoorthorhombic | twinning = Uncommon on {013} | cleavage = | fracture = Irregular/ uneven, sub-conchoidal | tenacity = Brittle | mohs = 6 - {{frac|6|1|2}} | luster = Sub-metallic | streak = | diaphaneity = Opaque | gravity = 7.03 - 7.23 | 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 name=Mindat>[http://www.mindat.org/min-2059.html Mindat.org - Ixiolite]</ref><ref name=HBM>{{cite web|title=Ixiolite|url=http://www.handbookofmineralogy.com/pdfs/ixiolite.pdf|work=Handbook of Mineralogy|publisher=Mineralogical Society of America|access-date=20 February 2013|archive-date=10 October 2012|archive-url=https://web.archive.org/web/20121010135550/http://www.handbookofmineralogy.com/pdfs/ixiolite.pdf}}</ref><ref name=Webmin>[http://www.webmineral.com/data/Ixiolite.shtml Ixiolite data on Webmineral]</ref><ref name=Mineralienatlas>https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Ixiolite Mineralienatlas</ref> }}
'''Ixiolite''' is an accessory oxide mineral found in granitic pegmatites. It is an oxide with the general chemical formula {{chem2|(Ta,Nb,Sn,Mn,Fe)4O8}} or {{chem2|(Ta,Mn,Nb)O2}}.
==Structure== Ixiolite was originally reported as crystallizing in the monoclinic crystal system.<ref Name=HBM/> Detailed studies of the scandium, tin and titanium rich varieties indicate that they form crystals in the orthorhombic system whereas tungsten ixiolite is monoclinic.<ref name=Wise/>
==Discovery and occurrence== It was first described in 1857 for an occurrence at Skogsböle, Kimito Island, Finland. The name is for ''Ixion'', the Greek mythological character related to ''Tantalus,'' as the mineral contains tantalum.<ref name=Mindat/>
Ixiolite is typically associated with feldspar, tapiolite, cassiterite, microlite, and rutile.<ref name=HBM/>
==Substitution and varieties== Trace elements include zirconium, hafnium, titanium and tungsten.<ref name=HBM/>
As with other tantalum and niobium bearing minerals considerable substitution and a number of varieties exist. Substitutions in the formula are common and the varieties stannian ixiolite (tin), titanian ixiolite (titanium) and wolframian ixiolite (tungsten) have been reported.<ref name=Wise>{{Cite journal |author=Wise, M.A. |author2=Černý, P. |author3=Falster, A.U. |year=1998 |title=Scandium substitution in columbite-group minerals and ixiolite |journal=Canadian Mineralogist |volume=36 |pages=673–680 |url=http://rruff.info/rruff_1.0/uploads/CM36_673.pdf}}</ref>
Scandium is present in many ixiolite sample with percentages up to 4.0 percent Sc<sub>2</sub>O<sub>3</sub>, but usually less than one percent scandium oxide. High scandium ixiolites, containing from 4 to 19% scandium oxide are typically also rich in tin and titanium.<ref name=Wise/>
==Economic importance== Ixiolite together with microlite, tantalite, tapiolite, wodginite are the most important minerals mined for the element tantalum. Ixiolite contains about 69 % tantalum oxide (Ta<sub>2</sub>O<sub>5</sub>) and is a common constituent of coltan ore.<ref name=bgs>{{cite web|title=Niobium-Tantalum|url=http://www.bgs.ac.uk/downloads/start.cfm?id=2033|publisher=bgs.ac.uk|access-date=2 March 2013}}</ref>
==Further reading== * {{Cite journal |vauthors=Grice JD, Černý P, Ferguson RB |year=1972 |title=The Tanco pegmatite at Bernic Lake, Manitoba. II. Wodginite, tantalite, pseudo-ixiolite and related minerals |journal=The Canadian Mineralogist |volume=11 |pages=609–642 |url=http://rruff.info/rruff_1.0/uploads/CM11_609.pdf}} * {{Cite journal |vauthors=Grice JD, Ferguson RB, Hawthorne FC |year=1976 |title=The crystal structures of tantalite, ixiolite and wodginite from Bernic Lake, Manitoba I. Tantalite and ixiolite |journal=The Canadian Mineralogist |volume=14 |pages=540–549 |url=http://rruff.info/rruff_1.0/uploads/CM14_540.pdf}} * [http://canmin.geoscienceworld.org/content/14/4/550.extract The crystal structures of tantalite, ixiolite and wodginite from Bernic Lake, Manitoba; II, Wodginite]
==References== {{Reflist}}
Category:Oxide minerals Category:Orthorhombic minerals Category:Minerals in space group 60