Lijst van fluorescerende mineralen


SCHEELITE


Scheikundige formule: CaWO4

Familie: Tungstaten, Molybdaten

Status: IMA-GP

Kristal Systeem: Tetragonaal

Mineraal om tentoon te stellen: Ja

Fluorescerende variëteiten:  cuproscheelitemolybdoscheelite

Fluorescentie:


UV Type Kleur Intensiteit Frequentie van de observatie
Lange Golven (365nm):      Violet roos Zeer zwak
Korte Golven(254 nm):      Blauw wit Zeer sterkAltijd
    
Andere kleuren lange golven:     
Violet rood ,
Andere kleuren korte golven:     
Witte ,

Daglicht foto


SCHEELITE, China
Photo and Copyright: James Hamblen
Site of the author
Used with permission of the author

Korte golf foto (254nm)


SCHEELITE under UVSW
Photo and Copyright: James Hamblen
Site of the author
Used with permission of the author

 

Foto galerij:

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     Naar de volledige galerij (8 beelden in totaal)


Fosforescentie (in de algemene betekenis) zien met het blote oog:


No Data

Thermoluminescencie: Ja


Commentaar:


A very thin  coating of SCHEELITE on WOLFRAMITE makes it glow and give the impression that this mineral is luminescent.


Activator en spectrum:


Voornaamste Activator: WO42-

Andere activatoren: Sm3+ , Eu3+ , Dy3+ , Tb3+ , Pr3+ , Nd3+ ,

Pieks in het spectrum (nm):

WO42-: Broad band centered at 425 - 435nm
Tb3+: 439nm
Dy3+: 488, 575nm
Sm3+: 609, 647nm
Pr3+: 607nm


Spectrum: Michael Gaft, Petah Tikva, Israel. Plot: Institute of Mineralogy, University of Vienna, Austria, with permission of the authors.

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  Vers la galerie de spectres (9 spectres au total)


Commentaar over activators en spectra:


Broad band centered at 425 - 435 nm activator: (WO4)2- ;
Peaks in relation with the presence of REE: 488 et 575 (Dy3+), 609 et 647 (Sm3+), 439 (Tb3+) et 607 (Pr3+); the pegmatitic and hydrothermel scheelite  shows the lines of Erbium and Terbium, while scheelite occurences related to eruptive complexe and sulfide ore shows dominantly the lines of the REE of the Cerium group.
Green emission due to (MoO4)2-(Tarashchan) or possibly Pb (Blasse).
The natural photoluminescence emission of ordered CaWO4 is attributed to an intrinsic slight distortion of the [WO4] tetrahedral.
Lifetime: 9μs (@ 405nm);

The color of the fluorescence of scheelite gives an idea of the unwilled presence of molybdenium in the ore. Concentrate of scheelite not penalized for molybdenium have a distinct blue fluorescence color. Those that fluoresce white are borderline  and contain roughly 0,35% to 1% of Mo. And scheelite that fluoresces distinctly yellow contains more than 1% corresponding to a transition to powellite. Higher than 4,8%, the yellow fluorescence color stays unchanged and cannot anymore be used as an indication of the percentage of Mo. Using this property, a method was  developped by R.S. Canon jr. (1942) while studying tungsten deposits in the seven Devils mining district of Idaho. A serie of finely powdered synthetic preparation or natural ore of known composition are permanently mounted in circular areas on a black card, being placed in order of increasing molybdenium content. There are twelve standard values on the card: 0,05, 0,19, 0,33, 0,48, 0,72, 0,96, 1,4, 2,4, 3,4, and 4,8% plus a pure calcium molybdate (48% Mo). Alternating with the covered circle are circular holes of the same size. The card is used by placing a hole over a powdered sample of the scheelite ore to be tested and comparing the fluorescence color of the sample with those of the adjacent standards. The sample will be found to have a fluorescence color according or between two standards and hence the approximate composition could be defined.


Beste vindplaats voor fluorescentie(*):


(*)Gegevens zijn niet exhaustieve, ze zijn beperkt tot de meest belangrijke plaatsen voor fluorescentie


Referentie voor fluorescentie:



Referentie voor luminenscentie op het internet:



Mineralogische Referentie op het internet:


  http://www.mindat.org/show.php?name=Scheelite

  http://webmineral.com/data/Scheelite.shtml

Onderzoek op Internet:

  Beelden op 'Google Image'

  Dokumenten in het Nederlands op Google

  Dokumenten in alle talen op Google

  Onderzoek op Wikipédia


 

Note: While all due attention has been paid to the implementation of the database, it may contain errors and/or accidental omissions. By nature, the database will always be incomplete because science always evolves according to new analysis.
A request providing no result means only that no such reference exists in the database, but it does not mean that what you are looking for does not exist, just not to our knowledge. If you think you have found an error or omission, please let us know via the contact page being sure to cite the source of information.

 


Snel opzoeking van een fluorescerend mineraal: