Tapiolite

{{Infobox mineral | name = Tapiolite | boxwidth = | boxbgcolor = | image = Tapiolite-121701.jpg | imagesize = 260 | alt = | caption = | category = | formula = (Fe, Mn)(Nb, Ta)₂O₆ | IMAsymbol = Tap<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 = | dana = | system = Tetragonal | class = Ditetragonal dipyramidal (4/mmm) <br/>H-M symbol: (4/m 2/m 2/m) | symmetry = ''P''4₂/mnm | unit cell = | color = | colour = | habit = | twinning = | cleavage = | fracture = | tenacity = | mohs = | luster = | streak = | diaphaneity = | gravity = | 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>[https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Tapiolite Mineralienatlas]</ref> }} '''Tapiolite''' [(Fe, Mn)(Nb, Ta)₂O₆] is a black mineral series that is an ore of niobium and tantalum. The tapiolite group includes tapiolite-(Fe) or ferrotapiolite and tapiolite-(Mn) or manganotapiolite.<ref name=Mindat>[http://www.mindat.org/min-3887.html Mindat tapiolite group]</ref><ref>[http://rruff.info/doclib/hom/ferrotapiolite.pdf Ferrotapiolite in the Handbook of Mineralogy]</ref><ref>[http://rruff.info/doclib/hom/manganotapiolite.pdf Manganotapiolite in the Handbook of Mineralogy]</ref> Tapiolite-(Fe) is by far the more common of the two.<ref name=MindatFe>[http://www.mindat.org/min-1531.html Tapiolite-Fe on Mindat]</ref><ref name=MindatMn>[http://www.mindat.org/min-2523.html Tapiolite-Mn on Mindat]</ref>

The minerals have a submetallic luster and a high specific gravity with tapiolite-Fe having a higher specific gravity (7.90)<ref name=MindatFe/> versus 7.72 for tapiolite-Mn.<ref name=MindatMn/>

The mineral was named in 1863 after the forest god Tapio of Finnish mythology, and the original tapiolite material came from Sukula, Tammela, Kanta-Häme, Finland.<ref name=Mindat/><ref>[http://webmineral.com/data/Tapiolite.shtml webmineral Tapiolite]</ref>

Tapiolite is very close to ''columbite'' and ''tantalite''. Those minerals have the same chemical composition, but different crystal symmetry orthorhombic for tantalite or columbite and tetragonal for tapiolite.<ref>P. Cerny et al. "The tantalite-tapiolite gap: natural assemblages versus experimental data" Canadian Mineralogist 30 (1992) 587 [http://rruff.geo.arizona.edu/doclib/cm/vol30/CM30_587.pdf free download]</ref>

{{Gallery |align=right |File:Tapiolite.GIF|Crystal structure of tapiolite }}

==References== {{reflist}}

{{Manganese minerals}}

Category:Tantalum minerals Category:Niobium minerals Category:Iron(II) minerals Category:Manganese(II) minerals Category:Oxide minerals Category:Tetragonal minerals Category:Minerals in space group 136 Category:Minerals described in 1863

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