Database of luminescent Minerals

WILLEMITE

Chemical Formula: Zn₂SiO₄

Familly: Silicates

Status: IMA-GP

Crystal System: Hexagonal

Mineral for Display: Yes

Luminescence:

Daylight Picture

WILLEMITE, Franklin, New Jersey, USA;
Photo and Copyright: James Hamblen
Site of the author
Used with permission of the author

Short Waves Pictures (254nm)

WILLEMITE under UVSW, Franklin, New Jersey, USA;
Photo and Copyright: James Hamblen
Site of the author
Used with permission of the author

Galerie de photos:

     To the gallery (14 images in the gallery)

Phosphorescence (in the common meaning of the term) seen by naked eye:

Thermoluminescence: Yes

Comments:

Variété troostite : willémite manganèsifère ;
beta-willemite nom erroné appliqué a une variété trouvée à Franklin-Sterling Hill et fluorescente en jaune ;
Certains échantillons de Brandtite fluorescents en vert OC devraient leur fluorescence à la willemite associée ;

Prior to the development of halophosphor in 1942, the first generation of phosphor used in fluorescent tube was  synthetic willemite activated with manganese-II. 

Main Activator(s) and spectrum:

Most Common Activator: Mn²⁺

Peaks in the spectrum (nm):

Mn²⁺ replacing Zn²⁺ : broad band peaking at +/- 525nm 

Comments on activators and spectra:

Lifetime: 400μs @520nm

The action of ultra-violet rays on a large series of minerals of all kinds was tested by G. F. Kunz and C. Baskerville in 1903, and by E. Engelhardt in 1912. T. Liebisch in 1912 determined spectroscopically the nature of the green fluorescence from willemite. W.S. Andrews has pointed out in 1922 that artificially prepared willemite is only active when it contains some manganese, the shade of the green fluorescence depending on the amount of manganese present. Palache (1928) confirmed that the willemite containing manganese fluoresces the strongest.

Dake (1941) stated that most connoisseurs of fluorescent minerals agree that willemite from Franklin an Ogdensburg, N.J. is the most spectacular of all luminescent minerals.

Best Locality for luminescence(*):

• Franklin Mine, Franklin, Sussex County, New Jersey, USA;
• Sterling Hill Mine, Ogdensburg, Sussex County, New Jersey, USA;
• Hogan Claim, near Wickenburg, Yavapai County, Arizona, USA (Green SW associated with calcite and fluorite);
• Desert View Mine, Holcomb Valley, San Bernardino County, California, USA (green SW associated with calcite red SW and sometimes hardystonite blue SW);
• Desert View Mine, Fawnskin (Grout), Bear Valley District, San Bernardino Mts, San Bernardino Co., California, USA;
• Purple Passion Mine, Red Picacho District, Wickenburg area, Yavapai Co., Arizona, USA;
• El Refugio Mine, Sinaloa, Mexico (green SW associated with hydrozincite blue-white SW)(+/-2007)
• Star Zinc Mine, Broken Hill, North Western province, Zambia;
• Excelsior prospect, Lusaka, Zambia;
• Hasselhojden, Grythyttan, Hällefors, Västmanland, Sweden;
• Garpenberg Norra Mine, Garpenberg, Hedemora, Dalarna, Sweden (green SW associated with calcite SW red pretty like Franklin specimens, with sometimes sphalerite SW yellow and hydrozincite SW blue);
• Berg Aukas, Grootfontein District, Otjozondjupa Region  Namibia;

(*)Data are not exhaustive and are limited to the most important localities for fluorescence

Bibliographical 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 ,
• Collecting Fluorescent Minerals, Stuart Schneider, Schiffer Publishing, 2004, ISBN 0-7643-2091-2 ,
• Luminescence Spectroscopy of Minerals and Materials, M. Gaft, R. Reisfeld, G. Panczer, Springer Editor, ISBN: 10 3-540-21918-8 ,
• Luminescent Spectra of Minerals, Boris S. Gorobets and Alexandre A. Rogojine, Moscow, 2002 ,
• Ultraviolet Light and Fluorescent Minerals, Th. Warren, S. Gleason, R. Bostwick, et E. Verbeek, 1995, ISBN 0-9635098-0-2 ,
• Franklin Website: http://franklin-sterlinghill.com ,
• Mt St Hilaire Website: http://www.saint-hilaire.ca ,
• Luminescenza nel regno minerale, Guido Mazzoleni, fotografia Roberto Appiani, Libri Sandit, 2010, ISBN 978-88-95990-63-7 ,
• Handbook of Fluorescent Gems and Minerals, a practical guide for the gem and mineral collector, Jack de Ment, 1949 ,

Luminescence Reference on internet:

• THE MINERALS OF FRANKLIN AND STERLING HILL, NEW JERSEY, ALBERT S. WILKERSON, BULLETIN 65 NEW JERSEY GEOLOGICAL SURVEY, 1962
• Franklin Mining District (Mindat.org)
• Franklin Mine, Franklin, Sussex County, New Jersey, USA;
• Sterling Hill Mine, Ogdensburg, Sussex County, New Jersey, USA;
• The Langesundsfjord: history, geology, pegmatites, minerals, Alf Olav Larsen, Bode Verlag Gmbh, 2010 ISBN 978-3-925094-97-2
• Der Aufschluss, Vol.48, n°2 March/April 1997 Langban minerals by Fritz Blatter;
• http://www.minersoc.org/pages/Archive-MM/Volume_21/21-119-388.pdf
• http://www.minerant.org/archief/fluo-Belgie.pdf

Pictures:

• Hasselhojden, Sweden: http://www.mindat.org/photo-174164.html
• Garpenberg Norra Mine, Sweden : https://www.mindat.org/photo-615793.html
• Desert View Mine, Ca, USA

Mineralogical Reference on internet:

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

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

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