FLUORAPATITE

Fluorapatite is a calcium phosphate fluorine mineral of the apatite group. Analyses indicate much variation in arsenic, which is pervasive in orebody fluorapatite, and show minimal Mn substitution for Ca. Much work remains to be done on the characterization of local apatites.
The limited given data are slightly misleading in that they do not show completely the variation in Cl, OH, and F in local material. Midmembers between many species occur here; solid solutions of the fluorapatite, svabite, johnbaumite, turneaureite, hedyphane, and hydroxylapatite members of the group are common. Numerous specimens have compositions that plot near the mutual F-OH join for the above-listed minerals, with Cl a minor component.
An analysis of apparent johnbaumite was given as one of svabite by Palache, correctly for the time, inasmuch as johnbaumite was not known then and the compositional variation in the apatite group was not understood yet. Although a number of analyses of arsenian fluorapatite were obtained by [Dunn], there is none whose composition entered the svabite compositional space defined as (Ca > Pb,Sr,Ba)(As > P)(F > Cl,OH). Svabite is unknown from these deposits.
In general, Cl is not present in significant amounts in the high-temperature primary apatites, except for hedyphane and turneaureite. The six analyses given are all of blue and green apatites, but color is not a useful discriminant. There is minimal substitution of Pb, Sr, and Ba in local fluorapatite.
Fluorapatite is the most common member of the apatite group at Franklin, but is much less common at Sterling Hill; it is also found in the Franklin Marble. The apatite of Palache (1935) is mostly this species. It was reported by Nuttall (1822) and Penfield (1880); the extant data were summarized by Palache (1935). Much blue and green fluorapatite from the orebodies has been mislabeled as svabite, not known with certainty from here. The aquatite of Koening (1889) is a printer's misspelling for apatite.
Franklin fluorapatite occurs as prismatic crystals; they were reported by Frondel (1972) to be over a foot long, but few exceed 15 cm in length. They are commonly terminated by a shallow dipyramid, as figured by Palache (1935). Crystals may be crude or well-formed; resorbed edges are common on calcite-hosted crystals.
The color of local fluorapatite varies substantially: blue, green, and bluish green are the most common colors, and colorless, white, gray, and brownish hues are also known. The luster is vitreous, and the mineral is brittle. The density varies, in good part due to the pervasive substitution of arsenic discussed below. Fluorapatite fluoresces in ultraviolet with blue, violet-blue, or orange colors in shortwave ultraviolet (Bostwick, 1972), but the fluorescence may be absent or imperceptible. It is best verified by both X-ray and chemical means.
Fluorapatite occurs sparingly in a variety of textures with the silicate minerals and is stable as a high-temperature, primary mineral. It occurs as euhedral crystals, most commonly in association with calcite, and more commonly as massive to granular material in association with rhodonite, andradite, calcite, feldspars, pyroxenes, micas, willemite, franklinite, and other species. It occurs less commonly with hematite and with hardystonite. Palache (1935) noted many occurrences on Mine Hill, including the Buckwheat Mine, the Trotter Mine, and the Parker Mine, and observed that it occurred near pegmatite- marble contacts. It was illustrated from the Buckwheat Dolomite by Peters et al. (1983).
Fluorapatite is uncommon at Sterling Hill, but was found in 1983 as 2-cm rounded crystals in calcite and sphalerite on the 600 level at the southern end of the orebody. It was also found in 1977 associated with fluorite, calcite, franklinite, willemite, and graphite in the black-willemite zone on the 1400 level. See also Jenkins (1994).
Blue prismatic crystals are found within the Franklin Marble, but have not been studied. (Dunn, 1995)

Location Found:

Franklin and Ogdensburg

Year Discovered:

1823

Formula:

Ca₂Ca₃(PO₄)₃F

Essential Elements:

Calcium, Fluorine, Oxygen, Phosphorus

All Elements in Formula:

Calcium, Fluorine, Oxygen, Phosphorus

IMA Status:

Approved

Fluorescent Mineral Properties

Shortwave UV light:

Orange to bluish orange (orchid, peach), moderately bright to weak greenish-blue in Franklin Marble

Mid wave UV light:

Orange to bluish orange, weak greenish-blue in Franklin Marble

Longwave UV light:

Orange to bluish orange, weak greenish-blue in Franklin Marble

Additional Information:

Fluoresces usually brightest shortwave, but occasionally as bright mid-wave

To find out more about this mineral at minDat's website, follow this link Fluorapatite

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.649

Frondel, Clifford (1972). The minerals of Franklin and Sterling Hill, a checklist. NY.: John Willey & Sons. p.42

The Picking Table References

	PT Issue and Page	Description / Comment
View Issue	V. 61, No. 2 – Fall 2020, pg. 13	Minerals of the Apatite Supergroup at Franklin and Sterling Hill, With Historical Notes, Earl R. Verbeek and Richard C. Bostwick (Long article, fluorapatite details pg 19)
View Issue	V. 57, No. 2 - Fall 2016, pg. 17	Fluorescent Minerals of Franklin and Sterling Hill, N.J., Part 1, Richard C. Bostwick - Fluorapatite
View Issue	V. 45, No. 1 - Spring 2004, pg. 11	The 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 - Fluorapatite
View Issue	V. 41, No. 1 - Spring 2000, pg. 13	A Scheelite-bearing Assemblage From Franklin, New Jersey By Robert E. Jenkins II - Apatite
View Issue	V. 35, No. 1 - Spring 1994, pg. 21	Geology and Mineralogy of a Veinlet Assemblage Associated With Wollastonite-Bearing Rocks, Sterling Mine, Ogdensburg, New Jersey, Robert E. Jenkins II - Apatite
View Issue	V. 33, No. 2 - Fall 1992, pg. 10	The Check List of Franklin-Sterling Hill Fluorescent Minerals - Fluorapatite (Fluorescent Info)
View Issue	V. 18, No. 2 - September 1977, pg. 12	The Fluorescent Minerals of Franklin and Sterling Hill, NJ by Richard C. Bostwick - Fluorapatite
View Issue	V. 18, No. 1 - March 1977, pg. 6	Recent Mineral Occurances at Sterling Hill by Stephen Sanford - Apatite

Images


Fluorapatite (blue-green), garnet (light and dark brown), feldspar and willemite (grape) from Franklin, NJ. From the collection of, and photo by Robert A. Boymistruk.		Fluorapatite, garnet, feldspar and willemite from Franklin, NJ under shortwave UV light. The fluorapatite fluoresces orange, willemite green, and feldspar dark red, the garnet is non-fluorescent. From the collection of, and photo by Robert A. Boymistruk.


Fluorapatite (dark green-blue), grape willemite (burgandy red), calcite (white) and franklinite (black) from Franklin, NJ. 4" x 1 1/2". From the collection of, and photo by WP.		Fluorapatite, grape willemite, calcite and franklinite from Franklin, NJ under longwave UV light. The fluorapatite fluoresces dark orange, willemite green, calcite white to light red, the franklinite is non-fluorescent. 4" x 1 1/2". From the collection of, and photo by WP

Fluorapatite, grape willemite, calcite and franklinite from Franklin, NJ under midwave UV light. The fluorapatite is not fluorescing, willemite green, calcite red, the franklinite is non-fluorescent. 4" x 1 1/2". From the collection of, and photo by WP.		Fluorapatite, grape willemite, calcite and franklinite from Franklin, NJ under shortwave UV light. The fluorapatite fluoresces orange, willemite green, calcite orange-red, the franklinite is non-fluorescent. 4" x 1 1/2". From the collection of, and photo by WP.


Fluorapatite crystal (gray-green) on calcite (white) from the Sterling Hill Mine, Ogdensburg, NJ. Field of view 2 3/4" x 1 1/4". From the collection of, and photo by WP.		Fluorapatite crystal on calcite from the Sterling Hill Mine, Ogdensburg, NJ under shortwave UV light. The fluorapatite fluoresces weak dark orange and calcite orange-red. Field of view 2 3/4" x 1 1/4". From the collection of, and photo by WP.


Fluorapatite (dark green-gray), pyroxene (black), minor willemite and calcite (white) from Taylor Road Dump, Franklin, NJ. 2 1/2" x 1 3/4". From the collection of, and photo by WP.		Fluorapatite, pyroxene, minor willemite and calcite from Taylor Road Dump, Franklin, NJ under longwave UV light. The fluorapatite fluoresces very weak yellow, the pyroxene is non-fluorescent. 2 1/2" x 1 3/4". From the collection of, and photo by WP.

Fluorapatite, pyroxene, minor willemite and calcite from Taylor Road Dump, Franklin, NJ under midwave UV light. The fluorapatite fluoresces moderate yellow to pink-purple, calcite red, the pyroxene is non-fluorescent. 2 1/2" x 1 3/4". From the collection of, and photo by WP.		Fluorapatite, pyroxene, minor willemite and calcite from Taylor Road Dump, Franklin, NJ under shortwave UV light. The fluorapatite fluoresces weak yellow to pink-purple, calcite red, wllemite green and the pyroxene is non-fluorescent. 2 1/2" x 1 3/4". From the collection of, and photo by WP.