Editing Scheelite (section)

{{Short description|Calcium tungstate mineral}}
{{For|the community in California|Scheelite, California}}
{{Use dmy dates|date=April 2025}}
{{Infobox mineral
| name        = Scheelite
| category    = Tungstate mineral
| boxwidth    = 
| boxbgcolor  =#ee964b 
| image       = Scheelite-224167.jpg
| imagesize   = 260px
| caption     = 
| formula     = CaWO<sub>4</sub>
| IMAsymbol   = Sch<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      = 7.GA.05
| system      = [[Tetragonal]]
| class       = Dipyramidal (4/m) <br/>[[H-M symbol]]: (4/m)
| symmetry    = ''I''4<sub>1</sub>/a
| unit cell   = ''a'' = 5.2429(3),&nbsp;Å <br/>''c'' = 11.3737(6)&nbsp;Å; ''Z''&nbsp;=&nbsp;4
| color       =  Colorless, white, gray, dark brown, brown, tan, pale yellow, yellow-orange, golden yellow, pale shades of orange, red, green, etc.; colorless in transmitted light and may be compositionally color zoned
| habit       = Pseudo-octahedra, massive, columnar, granular
| twinning    = Common, penetration and contact twins, composition plane {110} or {001}
| cleavage    = On {101}, distinct; on {112}, interrupted; on {001}, indistinct
| fracture    = Subconchoidal to uneven 
| tenacity    = Brittle
| mohs        = 4.5–5
| luster      = Vitreous to adamantine
| refractive  = ''n''<sub>ω</sub> = 1.918–1.921, ''n''<sub>ε</sub> = 1.935–1.938
| opticalprop = Uniaxial (+)
| birefringence = δ = 0.017
| pleochroism = Definite dichroic in yellow (yellow to orange-brown)
| streak      = White
| gravity     = 5.9–6.1
| melt        = 
| fusibility  = With difficulty
| diagnostic  = 
| solubility  = Soluble in alkalis. Insoluble in acids
| diaphaneity = Transparent to opaque
| other       = Fluorescence under short-wave UV is bright blue, bluish white to yellow.  Specimens with more molybdenum tend to fluoresce white to yellow, similar to powellite. Occasionally fluoresces red under mid-wave UV.
| references  = <ref name=Handbook>http://rruff.geo.arizona.edu/doclib/hom/scheelite.pdf Handbook of Mineralogy</ref><ref name=Mindat>http://www.mindat.org/min-3560.html Mindat.org</ref><ref name=Webmin>http://webmineral.com/data/Scheelite.shtml Webmineral data</ref><ref name=Klein>Klein, Cornelis and Cornelius S. Hurlbut, ''Manual of Mineralogy'', Wiley, 20th ed., 1985, p. 356 {{ISBN|0-471-80580-7}}.</ref>
}}

'''Scheelite''' is a [[calcium]] tungstate [[mineral]] with the [[chemical formula]] [[calcium|Ca]][[tungsten|W]][[oxygen|O]]<sub>4</sub>. It is an important [[ore]] of [[tungsten]] (wolfram). Scheelite is originally named after Swedish chemist [[Carl Wilhelm Scheele]] (1742–1786). Well-formed [[crystal]]s are sought by collectors and are occasionally fashioned into [[gemstone]]s when suitably free of flaws. Scheelite has been [[Chemical synthesis|synthesized]] using the [[Czochralski process]]; the material produced may be used to [[diamond simulant|imitate diamond]], as a [[scintillator]], or as a [[solid|solid-state]] [[lasing medium]]. It was also used in [[Radium#Luminescent paint|radium paint]] in the same fashion as was [[zinc sulphide]], and [[Thomas Edison]] invented a [[fluoroscope]] with a calcium [[tungstate]]-coated screen, making the images six times brighter than those with [[barium]] [[platinocyanide]]; the latter chemical allowed [[Wilhelm Röntgen|Röntgen]] to discover [[X-rays]] in early November 1895. The semi-precious stone marketed as 'blue scheelite' is actually a rock type consisting mostly of calcite and dolomite, with occasional traces of yellow-orange scheelite.