{{short description|Rare phosphate mineral}} {{Infobox mineral | name = Babefphite | category = Phosphate mineral | boxwidth = | boxbgcolor = | image = | imagesize = | caption = | formula = BaBe(PO<sub>4</sub>)(F,OH) |IMAsymbol=Bbf<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.BA.15 | system = Triclinic<ref name=atlas/><ref name=HBM/> | class = Pedial (1) <br/><small>(same H-M symbol)</small> | symmetry = ''F1'' | unit cell = a = 6.889&nbsp;Å, b = 16.814&nbsp;Å, <br/>c = 6.902&nbsp;Å; α = 90.01°, <br/>β = 89.99°, γ = 90.32°; Z&nbsp;=&nbsp;8<ref name=HBM/> | color = White | habit = As anhedral, equant to flattened grains, to 1.5 mm; may be in aggregates, (pseudotetragonal) | twinning = | cleavage = | fracture = | tenacity = Brittle | mohs = 3.5 | luster = Vitreous | refractive = nω = 1.629 nε = 1.632 | opticalprop = Uniaxial (+)<ref name=Mindat/> – biaxial positive (pseudouniaxial)<ref name=HBM/> | birefringence = 0.003 | pleochroism = | streak = White | gravity = 4.31 | density = | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Transparent | other = | references = <ref name=atlas>[https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Babefphite Mineralienatlas]</ref><ref name=Mindat>{{cite web |url=http://www.mindat.org/min-476.html |title=Babefphite |publisher=MinDat minerals database Accessed 1 December 2010 }}</ref><ref name=Webmin>{{cite web |url=http://webmineral.com/data/Babefphite.shtml| title=Babefphite |publisher=Webmineral Accessed 1 December 2010 }}</ref><ref name=HBM>[http://rruff.geo.arizona.edu/doclib/hom/babefphite.pdf Handbook of Mineralogy]</ref> }}

'''Babefphite''' is a rare phosphate mineral with the general formula BaBe(PO<sub>4</sub>)(F,OH). The name is given for its composition (Ba meaning barium, Be meaning beryllium, F meaning fluorine, and P for phosphorus).<ref>Fleischer, M (1966) New mineral names. American Mineralogist, 51, 1546–1553.</ref>

==Crystallography== Babefphite is tetragonal, which means crystallographically, it contains two horizontal and interchangeable equal axes (a<sub>1 and 2</sub>) and a longitudinal axis (c). It belongs to the 4/m 2/m 2/m point group; meaning it has four horizontal axes of twofold symmetry, two of which coincide with the crystallographic axes (a<sub>1</sub>) and (a<sub>2</sub>) and the remaining two at 45° to the (a<sub>1</sub>) and (a<sub>2</sub>).<ref>Klein, C., and Dutrow, B. (2007) The 23rd edition of the Manual of Mineral Science,675p. John Wiley and Sons, Inc. Hoboken, New Jersey, U.S.A.</ref><ref name=Wint>Wintringham, J.P. (1917) An Elementary Introduction to Crystallography. American Mineralogist, 2, 109–110.</ref>

== Optical properties == Babefphite is an anisotropic mineral meaning that the velocity of light passing through it will vary depending on the direction of travel. When measured against Canada Balsam it will display moderate positive relief. Relief is an optical property that relates the index of refraction of a mineral versus the index of refraction of another material. Positive relief denotes light being bent toward the mineral. Negative relief means the light is bent toward the mounting material. In the case of optical mineralogy, this other material is most often whatever material is used to mount the mineral in question in thin section.<ref name=HBM/> Based on the white color of babefphite in hand sample it is likely that it appears clear in thin section under plane polarized light. Due to its anisotropic nature, it has the possibility of displaying very weak pleochroism under the same conditions. Pleochroism is defined as a change of color, on rotation, of plane light. It occurs when the extraordinary and ordinary rays of light are absorbed differently, thereby displaying different colors. The wider the difference in the rays the more dramatic the color change. Babefphite is also weakly birefringent. Birefringence is an optical property that is determined by the direction that light passes through a mineral.<ref name=Wint/><ref>Neese, C., and Dutrow, B. (2007) 3rd edition Optical Mineralogy, 370p. Oxford University Press, Oxford, England</ref>

==Occurrence== Babefphite was first described in 1966 for an occurrence at the Aunik fluorite-rare metals deposit, Buryatia, Eastern-Siberian Region, Russia. It has also been reported from the Rožná pegmatite in the Vysočina Region, Moravia, Czech Republic.<ref name=Mindat/>

In the Siberian occurrence it occurs in residual material above rare-earth metal bearing skarns associated with alkaline intrusive bodies. It occurs with zircon, ilmenorutile, fluorite, phenakite, scheelite, bertrandite, albite, microcline and quartz.<ref name=HBM/>

==References== {{reflist}}

Category:Barium minerals Category:Beryllium minerals Category:Phosphate minerals Category:Triclinic minerals Category:Minerals in space group 1 Category:Minerals described in 1966