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Formula: Ca5(PO4)3F
Anhydrous phosphate containing halogen, apatite group
Epitaxial minerals: rutile, monazite and
carbonate-rich apatite (Mindat)
Specific gravity: 3.1 to 3.25
Hardness: 5
Streak: White
Colour: Colourless, yellow, green, blue and purple. Manganoan varieties are dark green and blue-green
Luminescence: Fluorapatite shows some of the widest variation in fluorescence found in the mineral kingdom. Eu2+,
Eu3+, Ce3+, Mn2+, Dy3+, Nd3+, Sm3+ and Sm2+
are the dominant activators of the luminescence; lead and antimony are common coactivators with Mn2+, and
other substituents such as (Fe2+ and Fe3+), cobalt and
nickel can act as luminescence quenchers. Combinations of different activators,
coactivators, and quenching elements, as well as other substituents that distort the fluorapatite structure and
shift crystal
field interactions, result in the wide range of luminescent colours and intensities found in fluorapatite.
Furthermore, different wavelengths of ultraviolet light may elicit different fluorescent responses from the same specimen.
Spatial variations of activators, coactivators, and quenching elements lead to zoning in fluorapatite fluorescence
(R&M 97.1.36-47, 96,1,20-23).
Solubility: Slightly soluble in sulphuric acid and moderately soluble in hydrochloric and nitric acids
Common impurities: OH,Cl,TR,La,Ce,Pr,Nd,Sm,Eu,Gd,Dy,Y,Er,Mn
Environments
Igneous environments
Pegmatites
Carbonatitess
Sedimentary environments
Metamorphic environments
Hydrothermal environments
Fluorapatite is the most common rock-forming phosphate mineral.
It occurs as an accessory in all types of igneous rocks, and is important in syenite,
alkaline rocks, carbonatites and granite pegmatites. It also occurs in
magnetite deposits, and is common in marble
and skarn, alpine-type fissures and hydrothermal tin
veins. It occurs in both regional and
contact metamorphosed rocks, especially crystallised
limestone associated with titanite,
zircon, pyroxene,
amphibole, spinel,
vesuvianite and phlogopite, also in
talc and chlorite
schist, as deposits of marine origin, as replacent beds of
limestone or coral via solutions derived from guano, as nodules disseminated
in nearshore sediments and in coal measures. It is an essential component of sedimentary
phosphorite, common as a detrital
or diagenetic component in oolitic ironstone and phosphatic carbonate rocks and
shale, and residual in laterite
(Dana, HOM).
Other associated minerals include albite, diopside,
forsterite, scapolite,
chondrodite, calcite and
magnetite
(HOM, Mindat).
Fluorapatite is usually fluorescent under long or short wave ultraviolet, cathode or X radiation, yellow under
long wave and bright orange-yellow under shart wave. The most common activator is Mn2+
(FLM). Some fluorapatite from the Foote mine, Kings Mountain, North Carolina, US, is green, near-opaque and
exhibits strong yellow fluorescence due to high abundance of Mn2+
(R&M 91-3:253).
Localities
There are three co-type localities, the Minillas Mine, Tambillos mining district, La Serena, Elqui Province, Coquimbo, Chile,
the Sauberg Mine, Ehrenfriedersdorf, Erzgebirgskreis, Saxony, Germany and the Holmbush Mine, Callington United Mines, Stokeclimsland,
Cornwall, England, UK.
At the Broken Hill district, Yancowinna county, New South Wales, Australia, the deposit originally formed in a shallow
lake or submarine rift and now comprises an intensely
granulite and upper
amphibolite facies metamorphosed and deformed
sequence of sedimentary and volcanic rocks, and minor iron-rich and
calc-silicate layers.
Quartz-feldspar
gneiss probably originated from
felsic volcanic rocks and associated
granitic intrusions, while
amphibolites reflect metamorphosed
mafic magmas originally emplaced as flows and associated intrusions.
Subaqueous hydrothermal precipitation involving ore fluids from crustal, magmatic, evaporitic, and possibly lacustrine
sources produced metal-rich deposits. Prolonged oxidation and weathering of the sulphide-rich orebodies in the
near-surface environment produced a zone greatly enriched in silver and
lead and many attractive, well-crystallised
secondary minerals. This oxidised zone has long been removed by
mining; current operations access the deeper, primary
sulphide-rich orebodies.
Specimens of fluorapatite from the primary ore are more
common, generally larger, and more aesthetic than those from
secondary assemblages and late-stage fractures. Within the
primary ore, the fluorapatite occurs in two major
associations: one in which fluorapatite is associated with sulphides such as
galena and sphalerite,
rhodonite and spessartine but
lacking significant amounts of calcite or
fluorite; in the other fluorapatite occurs with abundant
calcite and/or fluorite. Vitreous,
lustrous and translucent greenish-blue fluorapatite occurs as small (typically a few millimeters), squat,
rounded grains in sulphides, usually galena.
Rhodonite, spessartine, and less
commonly sphalerite and
chalcopyrite also occur. Rarer specimens have prismatic, brown, translucent
fluorapatite crystals up to a few centimeters long embedded in galena.
The largest Broken Hill fluorapatite crystals are typically several centimeters in length and occur in association
with calcite and/or fluorite. These
crystals are typically vitreous, lustrous, opaque, dark bluish-green or greyish-green, and they are commonly fractured,
bent, and sometimes broken and slightly displaced with the gap infilled with granular
calcite. Thin slivers of the fluorapatite are translucent and pale
bluish-green. Fluorite tends to be granular and occurs in patches that give the
appearance of a poorly defined fabric. Bustamite and
hedenbergite also may be present.
Fluorite, bustamite and
calcite may occur as inclusions in fluorapatite crystals. The most common
associate in the fluorapatite-calcite assemblage is a pale pinkish-brown
fluorite. Other specimens contain colourless
fluorite, and in both cases the
fluorite is readily identified by its blue fluorescence under longwave
ultraviolet light.
Fluorapatite also occurs in other but rare associations in the Broken Hill orebody. These include pale bluish-grey
fluorapatite associated with either gemmy crystals of pink bustamite
and minor calcite, hedenbergite
and galena, or associated with calcite,
bustamite, quartz, and minor
galena and sphalerite. A small, very
pale green fluorapatite from the NBHC mine and associated with
bannisterite has been found. There are two unusual fluorapatite
specimens purportedly coming from Broken Hill. One consists of an aggregate of pale green, granular fluorapatite,
and the other specimen has pale bluish, granular fluorapatite in a honeycomb-like siliceous matrix. Another unusual
specimen consists of a well-formed, pale greenish-yellow crystal associated with
chamosite from the Zinc Corporation mine.
The vast majority of fluorapatite specimens from Broken Hill that were examined under UV light are unresponsive
or fluoresce a dull yellow-orange, orange-red or blueviolet. One exception to this observation, however, is a specimen
with fluorapatite enclosed in galena that fluoresces a bright yellow. This
fluorescence possibly is caused by Mn2+ substituting for P
(R&M 97.1.16-26).
At Klemm's quarry, Moculta, South Australia, fluorapatite crystals to 3mm have been found scattered on
mitridatite
(AJM 17.1.16-17).
The Lake Boga granite, Lake Boga, Swan Hill Rural City, Victoria, Australia, is a very large intrusion formed about
365 million years ago. The entire outcrop of the granite is overlain by
sediments in places up to several hundred meters thick. The sole exposure into the
granite is the Lake Boga quarry, where the sediment is only a few metres
thick. The uppermost levels of the granite exhibit
aplite veins, pods of
pegmatite, and numerous miarolitic cavities, features that are
characteristic of the uppermost levels of a granite magma intruded to
shallow crustal levels.
Fluorapatite crystals were relatively common in the miarolitic cavities and
pegmatite patches before they were quarried out. Smoky
quartz,
orthoclase-microcline,
albite, muscovite and
schorl are common associates. The crystals are generally well-formed, ranging
from tabular to blocky, less commonly prismatic; prism faces are almost always striated. Some larger crystals have a thin
coating of drusy quartz and feldspar.
The most common colour of the fluorapatite is dull greyish-green to bluishgreen, but the largest and most
spectacular crystals are deep blue. Most large crystals show colour zoning that may involve dark and pale blue, green,
purple, lilac or colourless zones.
Lake Boga fluorapatite crystals contain small amounts of manganese,
strontium and uranium, that are responsible for the observed colour zonation, interpreted to represent episodes of
continuous or interrupted growth. The uranium concentration is significantly greater than in most fluorapatite in
granites and granitic
pegmatites throughout Australia.
The fluorapatite crystals contain a variety of inclusions; uraninite is
the most abundant, and monazite-(Ce),
cheralite-(Ce) and allanite-(Ce)
inclusions also occur
(R&M 97.1.28-32).
At Llallagua, Bolivia, fluorapatite occurred as a gangue mineral in cassiterite
veins. Fluorapatite crystals have been found on quartz and
ferberite crystals in many vugs. Most fluorapatite is covered by a crust of
wavellite. Some crystals occur on a stannite
matrix associated with jeanbandyite. Crystals filled with fine
jamesonite needles have also been found
(Min Rec 37-2.134).
In the Bancroft area, Ontario, Canada, fluorapatite crystals up to 45 cm long have been found in the
calcite vein-dikes
(R&M 94.5.412) .
At the poudrette quarry, Mont Saint-Hilaire, Quebec, Canada, fluorapatite is exceptionally high in thorium content
(R&M 95.2.164-165).
At Girardville, Quebec, Canada, fluorapatite is rare in the calcite-carbonatite
vein. Typical parageneses include phlogopite,
ilmenite, orthoclase and
aegirine
(R&M 88-5.431).
At the Yates Prospect, Otter Lake, Quebec, Canada, it appears that fluorapatite is a
primary mineral
that crystallised from a carbonate melt
(R&M 94.3.274-275).
At the Wutong mine, Guangxi, China, fluorapatite is intimately associated with
rhodochrosite and fluorite
(Min Rec 42-6.540).
At Yaogangxian, Hunan, China, fluorapatite is associated with
arsenopyrite, bournonite,
boulangerite, stannite,
ferberite, chalcopyrite,
quartz and fluorite
(Min Rec 42-6.580-581 ).
At Diako, Kayes region, Mali, fluorapatite has been found with epidote and with
garnet
(Min Rec 42-3.243 ).
At Cerro de Mercado, Durango, Mexico, fluorapatite is found embedded in masses of
sepiolite with quartz and
chalcedony, and with augite crystals in
breccia
(Min Rec 42-5.477-484).
At Imilchil, Er Rachidia Province, Drâa-Tafilalet, Morocco, fluorapatite is found in hydrothermally altered
syenite and nepheline syenite
(R&M 90.244-256).
At Anemzi, Imilchil, Er Rachidia Province, Drâa-Tafilalet, Morocco, fluorapatite occurs with a wide rane of associated minerals,
including microcline, chlorite,
magnetite, titanite,
actinolite, stilbite,
arfvedsonite, calcite,
epidote, prehnite,
hematite and hedenbergite
(R&M 90.244-256).
At Alchuri, Shigar Valley, Northern Areas, Pakistan, fluorapatite occurs on druses of
clinozoisite, and commonly on beds of
actinolite, and occasionally with diopside or
epidote
(Min Rec 37-6.535).
At Ekaterinburg, Ural mountains, Russia, fluorapatite occurs in mica
schist with beryl variety emerald and
chrysoberyl
(Dana).
At Palabora, Limpopo Province, South Africa, fluorapatite is a major constituent occurring in some of the cavities,
associated with fluoborite and rarely with
fluorite
(R&M 92.5.438).
At Jumilla, Murcia, Spain, fluorapatite was found in andesite
tuff
(Dana).
In the Erongo, Namibia, miarolytic cavities fluorapatite is rare, but it has been found as crystals on
quartz and schorl
(Min Rec 37.5.402).
At the the Karo Mine, Block D, Merelani Hills, Arusha Region, Tanzania, fluorapatite is found which contains fluid
inclusions, some of which contain graphite crystals
(R&M 88.2.162 and 178-183).
At the Carrock mine, Caldbeck Fells, Cumbria, England, UK, fluorapatite crystals to 3 cm occur on a
muscovite and quartz matrix, and crystals embedded in
quartz with pyrite have been found
(C&S).
At Tyllau Mwyn, Drws-y-nant, Gwynedd, Wales, UK, fluorapatite has been found in
stilpnomelane - bearing calcite veins
(MW).
At Prenteg, Tremadog, Gwynedd, Wales, UK, fluorapatite forms crystals to 1.5 mm associated with
rutile, chamosite and
albite
(MW).
At the Moiliili Quarry, Honolulu, Oahu, Honolulu county, Hawaii, USA, fluorapatite forms thin, needlelike
crystals within cavities of nepheline basalt,
associated with augite and nepheline
(R&M 92.3.226).
The Pulsifer pegmatite, West Mount Apatite Mining District, Auburn, Androscoggin county, Maine, USA, is a rare-element
granitic
pegmatite that intrudes upper
amphibolite facies
metamorphosed clay-rich rocks and
biotite
schists that are locally interbedded with
calc-silicate rocks. The
pegmatite exhibits five distinct zonations.
The border zone consists of fine to medium grained equi-granular quartz and
plagioclase, and minor biotite and
almandine.
The wall zone consists of slightly graphic K-feldspar,
quartz, biotite and
almandine.
The first intermediate zone is characterised by coarse-grained graphic feldspar
and plumose muscovite-quartz
aggregates.
Almandine and schorl are found as
accessory minerals, and rare beryl has been observed.
The first intermediate zone grades irregularly into a coarse-grained
plagioclase plus quartz plus
muscovite second intermediate zone.
The pocket zone assemblage, which lies below the second intermediate zone and immediately above the
garnet seam, consists primarily of
cleavelandite and quartz, although
locally blocky K-feldspar and
muscovite are also abundant. Gem
tourmaline, beryl, fluorapatite,
hydroxylherderite, gahnite,
almandine, columbite-(Mn)
and cookeite are among the minerals that have been found within the pocket zone.
The garnet seam is a 1 to 5 cm thick layer of 2 mm to 3 cm euhedral
almandine plus anhedral smoky quartz.
Just below the garnet seam lies a zone of undetermined thickness that is composed
primarily of blocky graphic albite.
Purple apatite is a rare variety of fluorapatite that is most prevalent in evolved
granitic
pegmatites. At the Pulsifer
pegmatite purple fluorapatite is typically found in
small mud-filled pockets within cleavelandite-rich areas immediately above the
garnet seam. The crystals typically show colour zoning, with dark purple rims
through lighter shades of purple to an almost white core. Fluorescence of Pulsifer purple fluorapatite varies
with the shade of purple colour. Under longwave ultraviolet radiation, deep purple-coloured areas display weak orange
fluorescence. The intensity of the orange fluorescence increases significantly in pale purple and white portions of
the crystals. Cathodoluminescence measurements from a few single crystals and fragments in general showed areas of bright
yellow-green cathodoluminescence emission corresponding to pale purple or white parts of the fluorapatite.
Portions of the crystals with deep purple colour were only weakly luminescent in the electron beam
(R&M 97.1.8-11).
At the Emmons pegmatite, Greenwood, Oxford county, Maine, USA, fluorapatite occurs as crystals to 3 cm. The best
crystals occur in vugs formed from alteration of beryl and on albite variety
cleavelandite and muscovite crystals in
miarolytic cavities. The fluorapatite is typically associated with bertrandite,
cookeite and Fe/Mn oxides after
siderite/rhodochrosite. The Emmons
pegmatite is an example of a highly evolved
boron-lithium-cesium-tantalum
enriched pegmatite
(R&M 94.6.507-508).
At the pegmatite at the Waisanen quarry, Greenwood, Oxford county, Maine, USA, fluorapatite occurs with a druse
of quartz prisms and rare oxidised pyrite cubes
on etched microcline and occasional muscovite
books. In some cases late stage albite appears as an overgrowth on the
microcline
(R&M 91-2.179-180).
At Acushnet Quarry, Bristol County, Massachusetts, USA, fluorapatite has formed in an Alpine cleft. Hydrothermal fluids,
associated with orogenic metamorphism, often deposit characteristic minerals, including
apatite, in these clefts. The metamorphic rocks exposed in the Acushnet quarry are
a mixture of schist, gneiss and intruded
diorite. Fluorapatite is found here on a
chlorite-covered matrix, associated with K-feldspar variety
adularia, albite variety pericline,
calcite, epidote,
muscovite, quartz,
titanite, chabazite and
stilbite
(R&M 90.244-256)
At a small beryl-rich unnamed pegmatite at Dickinson county, Michigan, USA, the dike is
well zoned with a massive quartz core, surrounded by
beryl crystals, fluorapatite and
niobium-tantalum species
(R&M 90-5.446).
At the Chickering Mine, Walpole, Cheshire county, New Hampshire, USA, fluorapatite is found in cavities that
formed by the dissolution of elbaite and, to a lesser extent, by the alteration of
spodumene within a quartz matrix
(R&M 90-5.416).
At the Adirondack mountains, New York, USA, fluorapatite occurs with with magnetite
(Dana).
Amity, Town of Warwick, Orange county, New York, USA, is an area of
granite intrusions into
marble and associated
gneiss. The marble is
mostly composed of white crystalline calcite that often has small flakes
or spheres of graphite and
phlogopite. Fluorapatite is found as large pale blue crystals to
10 cm in length, often associated with augite
(R&M 96.5.436).
At the tourmaline locality at Gouverneur, St. Lawrence county, New York, USA,
fluorapatite occurs rarely, with diopside and
tremolite in pockets in
calc-silicate rock
(R&M 91.6.523).
At the Harder farm, Hammond, St Lawrence county, New York, USA, fluorapatite occurs in
calcite
(R&M 85.5.461).
At The Dafoe Property, Pierrepont, St Lawrence county, New York, USA, fluorapatite occurs abundantly on the surfaces of some
tourmaline crystals
(R&M 94.5.452-455).
At the Foote Mine, Kings Mountain, North Carolina, USA, fluorapatite is found as masses and crystals in unaltered
spodumene-bearing pegmatites, and also as a hydrothermal mineral along fractures and
in solution cavities throughout the pegmatites and surrounding country rocks. In the primary stage of mineralisation
microcline, quartz and
spodumene crystallised from the melt, with accessory fluorapatite,
chlorite, muscovite, and
pyrrhotite. The second stage was the hydrothermal alteration of the
primary pegmatite minerals included leaching of elements and their enrichment
in the hydrothermal fluids. The third stage was the precipitation of secondary
phosphate and silicate minerals, the most abundant of which was fluorapatite. Fluorapatite is most commonly found with
albite, fairfieldite and
bikitaite
(R&M 91-3.250-256).
At South Foster, Providence county, Rhode Island, USA, fluorapatite crystals have been found in a road cutting at the white
schoolhouse on the hill just west of the town. They are developed along a contact line between fine grained
granite and a small mass of crystalline
limestone, in small open cavities associated with
biotite and scapolite
(AM7.28)
At the Clay Canyon variscite mine, Fairfield, Utah, USA, fluorapatite has been found as microcrystals in cavities
cementing fragments of crandallite
(Min Rec 41-4.338).
At the Belvidere Mountain Asbestos Quarries, Lowell/Eden, Vermont, USA, fluorapatite is fairly common in
schist and gneiss. It occurs locally in
the chlorite rock, and in the amphibolite
it sporadically occurs as a relict mineral
(R&M 90-6.533).
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