Database of luminescent minerals 

OPALE

Chemical formula: SiO₂ nH₂O

Status: IMA-GP

Crystal system : Amorphous

Display mineral: OUI

Associated names (luminescent varieties, discredited names, synonyms, etc.): cacholong,  hyalite,  hydrophane,  quincite (quincyite),  geyserite,  lussatite, 

Luminescence:

Daylight picture

OPALE, Nevada, USA;
Col. G. Barmarin; Photo: G. Barmarin

Longwave (365nm) picture

OPALE, Nevada, USA; LW (365 nm).
Col. G. Barmarin; Photo: G. Barmarin

Shortwave (254nm) picture

OPALE, Nevada, USA; SW (255 nm).
Col. G. Barmarin; Photo: G. Barmarin

Pictures Galery:

  
  Go to the galery (22 pictures)

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Phosphorescence (in the common sense of the term) observable with the naked eye:

Activator(s) and spectrum:

Activator(s): (UO₂)²⁺ (ion Uranyle) en impureté,

Peaks in the spectrum (nm):

UO₂²⁺ : 504nm, 524nm, 547nm, 569nm, 601nm (opale Nevada, USA)

Col. G. Barmarin; Spectre: G. Barmarin

Spectrum of OPALE in CSV

You can download the CSV file by clicking here: fichier csv

Spectrum Galery:

  
  Go to the galery (3 spectra)

Comments on spectrum and activators:

Green luminescence related to uranium impurities.
Georges O. Wild from Idar Oberstein in Germany found as early as 1947 that the greenish yellow fluorescence of opal from Virgin Valley, Nevada was due to uranium traces and being identical of the fluorescence of the synthetic gemstone Emerada (synthetic spinel).
Wild cites  a weak band  at 600 to 605nm, strong band at 570 to 578nm, strong band at 545 to 550nm, medium band at 522 to 527nm and weak band at 500 to 503nm.
Before Wild, DeMent has already studied the spectrum of opal s luminescence before Wild but not as precisely.

Best localities for fluorescence (*):

• Virgin Valley, Denio, Humboldt county, Nevada, USA (butterscotch colored common opal, strong green SW);
• Andamooka opal fields, Andamooka Ranges, Stuart Shelf, South Australia, Australia (weak white fluo);
• Stone Montain, Georgia, USA (strong yellow + yellow green phosphorescence);
• Crestmore, Ca, USA (strong yellow + yellow green phosphorescence);
• McLaughlin Mine (Manhattan Mine), Knoxville, Knoxville District, Napa Co., California, USA (yellow SW);
• Chalk Mountain Mine, Spruce Pine District, Avery Co., North Carolina, USA (green SW)

(*)The data are not exhaustive and are limited to a few remarkable localities for fluorescence

Bibliographic reference for luminescence:

• The Henkel Glossary of Fluorescent Minerals, Dr. Gerhard Henkel, Published by the FMS, 1989 ,
• Fluorescence: Gems and Minerals Under Ultraviolet Light, Manuel Robbins, 1994, Geoscience Press, ISBN 0-945005-13-X ,
• The World of Fluorescent Minerals, Stuart Schneider, Schiffer Publishing, 2006, ISBN 0-7643-2544-2 ,
• Handbook of Fluorescent Gems and Minerals, a practical guide for the gem and mineral collector, Jack de Ment, 1949 ,

Reference for luminescence on the Internet:

Mineralogical reference on the Internet:

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

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

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