Database of luminescent Minerals

GENTHELVITE

Chemical Formula: Zn₄Be₃(SiO₄)₃S

Familly: Silicates

Status: IMA-GP

Crystal System: Isometric

Mineral for Display: No

Luminescence:

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

Comments:

Discovered in Sterling (Franklin, NJ, USA) in 2002 in the Passaic Pit as tiny green fluorescing spots in amphibole.

Mt St Hilaire helvite can be reliably distinguished from genthelvite via its UV response (deep red vs green  (Horvath et al Min Rec 1990 etc.)

Main Activator(s) and spectrum:

Most Common Activator: Fe³⁺

Other activators:            Mn²⁺ ,

Peaks in the spectrum (nm):

(?) : Very large band peaking at 720nm with shoulder at 640nm (pink-red luminescence)

Comments on activators and spectra:

Genthelvite has been studied by steady-state luminescence spectroscopy and Mn²⁺ was found (Gorobets and Rogojine 2001).

Excitation by CW laser with 532 nm revealed one band peaking at 740 nm which is possibly connected to Fe³⁺ (Gaft)

Best Locality for luminescence(*):

• Poudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada;
• Bratthagen, Lågendalen (lagendalen), Hedrum, Larvik, Vestfold, Langesundfjord, Larvik Plutonic Complex, Norway;
• Wisconsin, USA (Blue-white SW);
• Nakalak Mt (Nakalaq; Nakkaalaaq), Taseq area, Ilímaussaq complex, Narsaq, Kujalleq, Greenland;
• Motzfeldt Centre, Igaliku (Igaliko), Narsaq, Kujalleq, Greenland;
• Passaic pit, Sterling Hill, Ogdensburg, Franklin Mining District, Sussex Co., New Jersey, USA;

(*)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 ,
• 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 ,
• Mt St Hilaire Website: http://www.saint-hilaire.ca ,

Luminescence Reference on internet:

• The Langesundsfjord: history, geology, pegmatites, minerals, Alf Olav Larsen, Bode Verlag Gmbh, 2010 ISBN 978-3-925094-97-2.




Images:




• Ogdensburg, New Jersey, USA: http://www.mindat.org/photo-10746.html
• Mont Saint-Hilaire, Québec, Canada: http://www.mindat.org/photo-171397.html

Mineralogical Reference on internet:

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

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

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