GENTHELVITE



Genthelvite, a rare zinc beryllium sulfur silicate mineral of the helvite group, was reported from Franklin by Essene and Peacor (1987) as microscopic grains associated with gahnite, sphalerite, titanite, petedunnite, and numerous other minerals. It was observed to be isotropic, with brilliant blue cathodoluminescence in the electron beam. It was identified on the basis of EDS analysis and its isotropic behavior. Genthelvite is apparently a very rare mineral at Franklin and has been found in only one very atypical sample which, though assuredly from Franklin, is not representative of Franklin specimens. (Dunn, 1995)

 Location Found: Franklin and Ogdensburg
     
 
 Year Discovered: 1944
     
 Formula: Zn4(Be3Si3O12)S
 Essential Elements: Beryllium, Oxygen, Silicon, Sulfur, Zinc
 All Elements in Formula: Beryllium, Oxygen, Silicon, Sulfur, Zinc
     
 IMA Status: Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
     
Fluorescent Mineral Properties
 Shortwave UV light: Blue-green of varying brightness
 Mid wave UV light: Blue-green of varying brightness, rarely yellow to orange
 Longwave UV light: Blue-green of varying brightness
     
 To find out more about this mineral at minDat's website, follow this link   Genthelvite

     
 References:
Dunn, Pete J. (1995). Franklin and Sterling Hill New Jersey: the world's most magnificent mineral deposits. Franklin, NJ.: The Franklin-Ogdensburg Mineralogical Society. p.369
The Picking Table References
 PT Issue and PageDescription / Comment
View IssueV. 61, No. 1 – Spring 2020, pg. 19Genthelvite from Franklin, New Jersey
View IssueV. 58, No. 2 - Fall 2017, pg. 15New Finds of Genthelvite at Sterling Hill, Ogdensburg, New Jersey, Earl R. Verbeek, PhD
View IssueV. 57, No. 2 - Fall 2016, pg. 18Fluorescent Minerals of Franklin and Sterling Hill, N.J., Part 1, Richard C. Bostwick - Genthelvite
View IssueV. 50, No. 2 - Fall 2009, pg. 38A Second Occurrence of Genthelvite From Sterling Hill, Ogdensburg, New Jersey (not much information)
View IssueV. 47, Combined Issue 2006, pg. 25A New Occurrence of Genthelvite From the Franklin Mine
View IssueV. 47, Combined Issue 2006, pg. 29Observable Genthelvite in the Petedunnite Assemblage From Franklin, NJ.
View IssueV. 44, No. 2 - Fall 2003, pg. 23Genthelvite From Ogdensburg, New Jersey
View IssueV. 44, No. 2 - Fall 2003, pg. 27Fluorescence Emission Spectrum of Genthelvite From Sterling Hill, New Jersey
     
Images
     
Genthelvite and calcite from the Passaic Pit, Sterling Hill Mine, NJ.Genthelvite and calcite from the Passaic Pit, Sterling Hill Mine, NJ. under longwave UV Light
Genthelvite (green) and calcite from the Passaic Pit, Sterling Hill Mine, NJ. From the collection of, and photo by JVF.
Genthelvite (green) and calcite from the Passaic Pit, Sterling Hill Mine, NJ under longwave UV light. The genthelvite fluoresces green and the calcite dull red. From the collection of, and photo by JVF.
Genthelvite and calcite from the Passaic Pit, Sterling Hill Mine, NJ. under shortwave UV Light
Genthelvite (green) and calcite from the Passaic Pit, Sterling Hill Mine, NJ under shortwave UV light. The genthelvite fluoresces weak green and calcite red-orange. From the collection of, and photo by JVF.

Genthelvite (gemmy) in calcite and franklinite matrix from Sterling Hill Mine, NJ
Genthelvite crystal (gemmy light green) in calcite and franklinite matrix from Sterling Hill Mine, NJ. Photo by Robert A. Boymistruk.






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