FLUOBORITE



Fluoborite is a magnesium boron fluorine mineral. Some hydroxyl substitutes for fluorine. The substitution of octahedral cations for Mg is ambiguous; modern analyses are lacking, and those of Bauer were done using admittedly impure material. Several of those analyses are given by Palache (1935). Little is known of the exact composition of local fluoborite.
Fluoborite was first reported from Sterling Hill, the second occurrence of the species, by Bauer and Berman (1929b, 1929d); their results were summarized by Palache (1935).
Fluoborite is white to colorless, occurring in subparallel fibrous masses, porcelaneous aggregates, and white fluffy aggregates and, in the Franklin Marble, as euhedral crystals. Much fluoborite is soft and flexible, and some is pulverent. The density is 2.92 g/cm3. Fluoborite is fluorescent in shortwave ultraviolet with a light yellowish-white color. It has physical similarity to sussexite and some fibrous amphiboles.
Fluoborite was first reported from Sterling Hill by Bauer and Berman (1929b) in two types of occurrences. It was found associated with rhodochrosite, pyrochroite, and zincite in a vein in franklinite-willemite-calcite ore. Here it occurs as capillary fluffy aggregates, occurring with mooreite, and is the last-formed mineral in the assemblage. Fluoborite was also found as subparallel fibrous aggregates, 3-5 centimeters in length, intimately associated with carbonates and bright orange zincite from Sterling Hill.
Fluoborite was found in small 1-3 mm crystals, associated with calcite, graphite, and possible chondrodite at the Franklin Quarry in Franklin.
Fluoborite is also found elsewhere in the Franklin Marble, specifically at the Lime Crest Quarry in Sparta and in 1-cm crystals at the Bodnar Quarries in Hamburg (Kearns, 1975), both outside of the Franklin-Sterling Hill Area as defined herein.
Although specimens labeled as being from the Franklin Mine are found in many collections, their provenance is not beyond question; such material has not yet been shown to be unambiguously from the Franklin Mine. (Dunn, 1995)

 Location Found: Franklin and Ogdensburg
     
 
 Year Discovered: 1926
     
 Formula: Mg3(BO3)(F,OH)3
 Essential Elements: Boron, Fluorine, Magnesium, Oxygen
 All Elements in Formula: Boron, Fluorine, Hydrogen, Magnesium, Oxygen
     
 IMA Status: Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
     
Fluorescent Mineral Properties
 Shortwave UV light: Moderately bright cream
     
 To find out more about this mineral at minDat's website, follow this link   Fluoborite

     
 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.640

Frondel, Clifford (1972). The minerals of Franklin and Sterling Hill, a checklist. NY.: John Willey & Sons. p.56
The Picking Table References
 PT Issue and PageDescription / Comment
View IssueV. 57, No. 2 - Fall 2016, pg. 17Fluorescent Minerals of Franklin and Sterling Hill, N.J., Part 1, Richard C. Bostwick - Fluoborite
View IssueV. 34, No. 2 - Fall 1993, pg. 15Recent Mineral Finds From The Sterling Mine Ogdensburg, New Jersey - Fluoborite
View IssueV. 33, No. 2 - Fall 1992, pg. 10The Check List of Franklin-Sterling Hill Fluorescent Minerals - Fluoborite (Fluorescent Info)
View IssueV. 27 No. 2 - Fall 1986, pg. 5Minerals of the Franklin Quarry, Philip P. Betancourt, Fluoborite
View IssueV. 18, No. 2 - September 1977, pg. 6Mineral Notes - Fluoborite
View IssueV. 18, No. 2 - September 1977, pg. 12The Fluorescent Minerals of Franklin and Sterling Hill, NJ by Richard C. Bostwick - Fluoborite
View IssueV. 17, No. 1 - March 1976, pg. 8Research Reports - Fluoborite
View IssueV. 15, No. 1 - February 1974, pg. 10Mineral Notes - Fluoborite (small article)
View IssueV. 7, No. 2 - August 1966, pg. 8The Minerals of Sterling Hill 1962-65 by Frank Z. Edwards - Fluoborite (small article)
     
Images
     
Fluoborite grains in calcite / marble, with graphite and pyrite, Sterling Hill MineFluoborite grains in calcite / marble, with graphite and pyrite, Sterling Hill Mine under shortwave UV Light
Fluoborite grains in calcite / marble, with graphite and pyrite from the Sterling Hill Mine, Ogdensburg, NJ. Photo by JVF.
Fluoborite grains in calcite / marble, with graphite and pyrite from the Sterling Hill Mine, Ogdensburg, NJ under shortwave UV light. The fluoborite fluoresces cream-white and the calcite / marble, graphite and pyrite is non-fluorescent. Photo by JVF.






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