Scheelite



Scheelite, a calcium tungstate mineral and the tungsten analogue of powellite, is less common than powellite locally; it has been verified in only one assemblage from Franklin, and probable scheelite was subsequently found at Sterling Hill.
At Franklin, scheelite occurs as isolated, anhedral crystals up to 1 cm; some are arranged linearly in a band in the observed specimens. This scheelite is subtranslucent, colorless to light gray, and has a resinous to adamantine luster. It is fluorescent in ultraviolet with a moderate yellow color in shortwave ultraviolet and a weaker yellow in longwave. Semiquantitative analysis shows it to have a composition of approximately CaO 20 wt. %, WO3 66 wt. %, and MoO3 12 wt. % and thus to contain approximately 75 mole % scheelite. The material described above was found near the Trotter Shaft, in a dark-colored matrix, associated with fluorapatite, pyroxmangite, microcline, willemite, and calcite. Scheelite was also found associated with secondary willemite and franklinite from Franklin.
At Sterling Hill, probable scheelite was found occurring in colorless 0.3-1.0 mm crystals associated with secondary epidote, manganaxinite, fluorite, and calcite just above the 1300 level. This probable scheelite has not been analyzed; it has a vivid bright blue fluorescence response color in ultraviolet. Unanalyzed material in the scheelite-powellite series was found associated with scapolite, a Ca-As apatite, and green-fluorescent chabazite on the 340 level in 1990. (Dunn, 1995)


 Location Found: Franklin and Ogdensburg
     
 
 Year Discovered: 1821
     
 Formula: Ca(WO4)
 Essential Elements: Calcium, Oxygen, Tungsten
 All Elements in Formula: Calcium, Oxygen, Tungsten
     
 IMA Status: Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
     
Fluorescent Mineral Properties

 Shortwave UV light: Bright yellow to cream to white, rarely bright blue
 Mid wave UV light: Bright yellow to cream to white
     
 To find out more about this mineral at minDat's website, follow this link   Scheelite

     
 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.644

Frondel, Clifford (1972). The minerals of Franklin and Sterling Hill, a checklist. NY.: John Willey & Sons. p.76


The Picking Table References
 PT Issue and PageDescription / Comment
V. 58, No. 1 - Spring 2017, pg. 16Fluorescent Minerals of Franklin and Sterling Hill, N.J., Part 2, Richard C. Bostwick - Scheelite
View IssueV. 45, No. 1 - Spring 2004, pg. 14The Art of Fluorescent Mineral Photography, With Special Attention to the Minerals of Franklin and Sterling Hill Photographing the More Popular Franklin and Sterling Hill Fluorescent Minerals - Scheelite
View IssueV. 41, No. 1 - Spring 2000, pg. 14A Scheelite-bearing Assemblage From Franklin, New Jersey By Robert E. Jenkins II - Scheelite
View IssueV. 33, No. 2 - Fall 1992, pg. 11The Check List of Franklin-Sterling Hill Fluorescent Minerals - Scheelite (Fluorescent Info)
View IssueV. 18, No. 2 - September 1977, pg. 17The Fluorescent Minerals of Franklin and Sterling Hill, NJ by Richard C. Bostwick - Scheelite
View IssueV. 13, No. 2 - August 1972, pg. 13The Fluorescent Minerals of Franklin/Ogdensburg Area by Frank Z. Edwards - Scheelite (Fluorescent Info)
View IssueV. 13, No. 1 - February 1972, pg. 10Franklin Mineral Notes - Scheelite/Powellite
View IssueV. 7, No. 1 - February 1966, pg. 9Scheelite
View IssueV. 6, No. 2 - August 1965, pg. 11Scheelite
     
Images

     
Scheelite and apatite in a pyroxene matrix from FranklinScheelite and apatite in a pyroxene matrix from Franklin under shortwave UV Light
Scheelite and apatite in a pyroxene matrix from Franklin, NJ. Photo by JVF.
Scheelite and apatite in a pyroxene matrix from Franklin, NJ under shortwave UV light. The scheelite fluoresces cream white and the apatite orange. Photo by JVF.







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