{{Short description|Rare-earth mineral series}} {{infobox mineral | name = Wakefieldite | category = Rare-earth mineral | boxwidth = | boxbgcolor = | image = Wakefieldite-(La) , Hausmannite - Grube Glücksstern, Gottlob, Thüringen.jpg | imagesize = 260 | alt = | caption = Wakefieldite-(La) on hausmannite | formula = ({{chem2|(La,Ce,Nd,Y)VO4}}) | IMAsymbol = Wf<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 = 8.AD.35 | 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 = | color = Canary-yellow, pale tan (Wakefieldite-(Y)); Dark red to coal-black, pale yellow to bluish gray (Wakefieldite-(Ce)); Light pink, brown (Wakefieldite-(La) | colour = | habit = Prismatic crystals, pulverulent masses | twinning = | cleavage = Good on {100} | fracture = | tenacity = Very brittle | mohs = 4–5 | luster = | streak = | diaphaneity = Translucent to opaque | gravity = 4.25 (calculated Wakefieldite-(Y)); 4.74 (meas. Wakefieldite-(Ce) | density = | polish = | opticalprop = Uniaxial (+) | refractive = ''n''<sub>ω</sub> = 2.000, ''n''<sub>ε</sub> = 2.140 | birefringence = | pleochroism = | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence= | absorption = | melt = | fusibility = | diagnostic = | solubility = | other = | alteration = | references = }} '''Wakefieldite''' ({{chem2|(La,Ce,Nd,Y)VO4}}) is an uncommon rare-earth element vanadate mineral. There are four main types described of wakefieldite- wakefieldite-(La), wakefieldite-(Ce), wakefieldite-(Nd), and wakefieldite-(Y), depending upon the dominant rare-earth metal ion present. Wakefieldite has a Mohs hardness ranging from 4 to 5.<ref>The Mineral and Locality Database, [http://www.mindat.org/min-35901.html ''Wakefieldite-(La)''].</ref> Wakefieldite forms crystals of tetragonal structure. In terms of crystal structure, it is the vanadate analog of the rare-earth phosphate mineral xenotime. Unlike xenotime, it is more favorable for wakefieldite to contain the lighter rare-earth elements over the heavier ones. Due to the lanthanide contraction, the heavier rare earths have smaller ionic radii than the lighter ones. When the phosphate anion is replaced by the larger vanadate anion, the tetragonal crystal system preferentially accommodates the larger light rare-earth elements.<ref>Miyawaki R., and I. Nakai. (1996). "Crystal Chemical Aspects of Rare Earth Minerals". Ed. Andrian P. Jones, Frances Wall, and C. Terry Williams. ''Rare Earth Minerals: Chemistry, Origin and Ore Deposits''. London: Chapman & Hall. (p. 29–30).</ref>
Wakefieldite was first described for an occurrence in the Evans Lou mine, St. Pierre de Wakefield, Quebec, Canada<ref>Miles, Norman M., et al., [http://www.minsocam.org/ammin/AM56/AM56_395.pdf ''Wakefieldite, Yttrium Vanadate, a New Mineral From Quebec''], American Mineralogist, Vol. 56, Mar.–Apr. 1971.</ref> and later designated Wakefieldite-(Y).<ref>[http://www.mindat.org/min-4234.html Mindat, Wakefieldite-(Y)].</ref>
==References== {{reflist}}
Category:Lanthanide minerals Category:Vanadate minerals Category:Tetragonal minerals Category:Minerals in space group 141