Images
Formula: CaF2
Fluoride
Varieties
Yttrofluorite is a variety of fluorite containing an appreciable amount of trivalent
yttrium (Y) taking the place of divalent
calcium (Ca) cations in the fluorite structure
(Mindat)
Images of fluorescing yttrofluorite
Properties
Crystal System: Isometric
Specific gravity: 3.175 to 3.56 measured, 3.181 calculated
Hardness: 4
Streak: White
Colour: Colourless, white, purple, green, blue, yellow, pink, red. Fluorite which is purple in daylight is
coloured by the Frenkel defect, where an electron displaces a fluorine F- ion, during growth or when
radiation displaces it from its usual position. A deep green daylight colour can be caused by the divalent samarium
ion Sm2+ and yellow by gadolinium Gd3+. Radiation from included or nearby radioactive atoms
releases atoms of calcium and fluorine from the fluorite, causing a very dark violet colour, and the rare and
beautiful pink fluorite from Switzerland is coloured by impurities of yttrium oxide YO2
(AM 52.1003-1008). Some fluorites are light blue because they contain an yttrium Y3+ ion substituting
for the calcium near a fluorine vacancy, which is populated by two electrons; this complex centre absorbs in the
violet and the yellow-green and so gives a blue hue
(G&G XXIV.11).
Solubility: Slightly soluble in hydrochloric acid; moderately soluble in sulphuric acid; slightly soluble in water
Melting point 1403°C, boiling point 2500°C.
Common impurities: Y,Ce,Si,Al,Fe,Mg,Eu,Sm,O,ORG,Cl,TR
Environments:
Plutonic igneous environments
Pegmatites
Carbonatites
Metamorphic environments
Hydrothermal environments
Hot spring deposits
Fluorite is a common and widely distributed mineral; it mainly occurs as a pore-filling mineral in
limestone and dolostone, and in
mesothermal (moderate temperature) and
hypothermal (high temperature) hydrothermal vein deposits associated with
lead and silver
ores. Less often it may be found as a primary mineral in
igneous rocks and pegmatites, where it is a late-stage mineral
following deposition of beryl, topaz and
tourmaline. It also may be precipitated at hot springs
(R&M 88-2:134).
In carbonatites it is associated with albite and
pyrite (HOM).
When fluorite occurs as a cavity fill in carbonate rocks it is usually associated with
calcite, dolomite,
anhydrite,
gypsum and sulphur.
In hornfels of contact metamorphic rocks
fluorite is associated with calcite and spinel
(AS).
In hydrothermal vein deposits, fluorite may be found with calcite,
dolomite, baryte,
galena,
sphalerite and molybdenite.
Fluorite may be found in
granite,
quartzolite and
dolostone.
Pseudomorphs of quartz after
fluorite
are common. Fluorite also forms
pseudomorphs after
calcite, baryte and
galena
(Dana).
Fluorescence
Fluorite is often, but not always, fluorescent, generally stronger under long wave than under short wave
ultraviolet. Pure fluorite, however, is colourless and perfectly transparent, and does
not fluoresce. The divalent europium ion Eu2+ is the most common activator, and causes intense blue
fluorescence. Other activators include divalent samarium Sm2+ causing red fluorescence, trivalent samarium
Sm3+, trivalent europium Eu3+, dysprosium Dy3+ causing yellow fluorescence, holmium
Ho3+, erbium Er3+, terbium Tb3+ and neodymium Nd3+, all these are rare earth
elements
(FLM).
Localities
At Rumsby's mine, New South Wales, Australia, indications are that fluorite was formed at temperatures between 451
and 462oC in intersecting vein systems in granite. The
paragenetic sequence included early stage smoky quartz,
arsenopyrite, ferberite,
bismuth, monazite,
fluorite,
beryl, ilmenite,
K-feldspar variety adularia, muscovite and
tourmaline group minerals. A later stage precipitated
quartz, muscovite,
chalcopyrite, pyrite and
chlorite group minerals. Secondary alteration replacement minerals
included scheelite after
ferberite, chalcopyrite,
pyrrhotite and cubanite,
hematite and rutile after
ilmenite and covellite
after chalcopyrite.
( AJM 18.2.26 )
At the Summit Cleft, Weißeck area, Muhr, Tamsweg District, Salzburg, Austria, in the summer of 2022, Reinhold
Bacher and his colleagues found what they first thought was a new pocket where they extracted spectacular
fluorite. In fact the area had been mined in the seventeenth century, as was evidenced by the discovery
of an old mediaeval mining chisel in the pocket.
The fluorite crystals reach edge lengths up to 6 cm; they are colour-zoned, from violet to dark blue,
pale blue, cyan and green, and in spite of the depth of colour they are transparent. They often show small
intergrown blades of white baryte, and purple spots most likely due to
low levels of radioactivity. They also show an alexandrite effect,
appearing different colours under different light sources
(Minrec 54.747-764).
Fluorite from the Summit Cleft - Image
The Fazenda Concórdia pegmatite, Mimoso do Sul, Espírito Santo, Brazil, is a
pegmatitic fluorite occurrence, with hunks of
pegmatite measuring from 6 cm to more than 35 cm,
hosting somewhat rough cubic crystals of greenish blue fluorite to a remarkable 20 cm on edge,
together with sizable crystals and cleavage sections of very pale green
amazonite.
The uncommon colour of the translucent, somewhat distorted fluorite crystals, together with their
occurrence in a pegmatite, make the specimens
interesting, although they are more impressive for size than for beauty
(Minrec 55.1.86).
At the Rock Candy Mine, Grand Forks, Greenwood Mining Division, British Columbia, Canada, quartz
pseudomorphs after fluorite have been found
(KL p251). The fluorite is generally pale greenish yellow and fluoresces bright blue
(Mindat photos).
Fluorite from the Rock Candy Mine - Image
At the Marron Volcanics of the Olalla Area South-Central British Columbia, Canada, fluorite has been found occurring as
clear, colorless octahedra to 1 mm, intimately associated with brewsterite
at the Yellow Lake road cut, and at a road cut along Highway 3A, green fluorite crystals to 1.5 mm have been found in
cavities in laumontite veins
(R&M 96.6.521-522).
At the Ontario Gem Mine, Thunder Bay District, Ontario, Canada, a specimen with fluorite crystals on quartz variety
amethyst has been found
(R&M 94.4.338).
rhodochrosite pseudomorphs after
fluorite have been found
(KL p162).
Fluorite from Mont Saint-Hilaire - Image
At the Pioneer quarry, Kwun Tong District, Kowloon, Hong Kong, China, the contact between
granite and tuff is very sharp,
and many veins and stringers of aplite and
pegmatite from the batholith invade the country rock. The
granite near the contact contains crystals of
fluorite, pyrite,
molybdenite and quartz, and
calcite-filled vugs. Calcite also
occurs along joint planes
(Geological Society of Hong Kong Newsletter 1.7.6).
At Devil's Peak, Sai Kung District, New Territories, Hong Kong, China, the mineralisation occurred in
quartz veins in the contact zone between a
granite intrusion and acid volcanic rocks. The mine is now closed,
and inaccessible for collecting.
Fluorite was commonly associated with topaz
(Hong Kong Minerals (1991). Peng, C J. Hong Kong Urban Council)
The Ma On Shan Mine, Ma On Shan, Sha Tin District, New Territories, Hong Kong, China, is an abandoned
iron mine, with both underground and open cast workings. The
iron ores contain
magnetite as the ore mineral and occur predominantly as masses of all sizes
enclosed in a large skarn body formed by contact metasomatism of
dolomitic limestone at the
margins of a granite intrusion. In parts of the underground workings
magnetite is also found in
marble in contact with the
granite. The skarn rocks
consist mainly of tremolite,
actinolite, diopside and
garnet.
Fluorite is found abundantly as small colourless irregular grains in the
skarn rocks, and also commonly filling veins and vugs in the
skarn, sometimes as crystals up to 1 cm in size, and often associated with
calcite, quartz,
serpentine or pyrite
(Hong Kong Minerals (1991). Peng, C J. Hong Kong Urban Council)
Fluorite from Ma On Shan - Image
The Needle Hill Mine, Needle Hill, Sha Tin District, New Territories, Hong Kong, China, is a tungsten mine, abandoned
in 1967. The principal ore is wolframite, and the principal gangue mineral is
quartz. Molybdenum also occurs. The
mineralisation consists of a series of parallel fissure veins that cut through
granite. Wolframite and
quartz are the main minerals, but galena,
sphalerite, pyrite,
molybdenite and fluorite have also
been found here
(Geological Society of Hong Kong Newsletter 9.3.29-40).
The quartz-wolframite veins are of
high-temperature hydrothermal formation,
and grade into wolframite-bearing
pegmatites.
(Hong Kong Minerals (1991). Peng, C J. Hong Kong Urban Council)
The Lin Fa Shan deposit, Tsuen Wan District, New Territories, Hong Kong, China, is located in a remote area of the
Tai Mo Shan
Country Park, on a steep west facing slope of Lin Fa Shan, just above the abandoned village of Sheung Tong. The
surrounding hillsides are covered with shallow excavations, representing past searches for
wolframite, the natural ore of
tungsten. The abandoned workings are extremely dangerous with unsupported tunnels, open shafts and no maintenance since
their closures in 1957; the workings should not be entered
(http://industrialhistoryhk.org/lin-shan).
Fluorite occurs as colourless or purplish granular masses in the
wolframite-bearing quartz veins and
greisen
(Hong Kong Minerals (1991). Peng, C J. Hong Kong Urban Council).
At the Xianghualing Mine, Xianghualing Sn-polymetallic ore field, Linwu County, Chenzhou, Hunan, China, fluorite occurs as
pale green, transparent, cubic crystals to 2.3 cm on edge
(AESS).
Fluorite from Xianghualing - Image
At the Xianghuapu Mine, Xianghualing Sn-polymetallic ore field, Linwu County, Chenzhou, Hunan, China, fluorite occurs as
colourless or green, transparent, cubic crystals to 2 cm on edge
(AESS).
Fluorite from Xianghuapu - Image
At Manaoshan Mine, Dongpo ore field, Suxian District, Chenzhou, Hunan, China, fluorite has veen found as simple cubes of
pale green, water-clear crystals up to 14 mm on edge, some of which have one or more faces frosted with a white, opaque mineral.
These are on a druse of small colourless, vitreous quartz crystals.
(AESS).
At the Yaogangxian Mine, Yaogangxian W-Sn ore field, Yizhang County, Chenzhou, Hunan, China, fluorite crystals occur as
mauve, water-clear, sharp, simple cubes
(AESS).
Fluorite from Yaogangxian - Image
At Shangbao, fluorite crystals occur as colourless, pale purple or green, water-clear, sharp, simple cubes, associated with
dolomite
(AESS).
Fluorite from Shangbao - Image
The Bairendaba Ag-polymetallic deposit, Hexigten Banner, Chifeng City, Inner Mongolia, China, is a mesothermal
magmatic-hydrothermal vein-type silver -
lead - zinc deposit, hosted in
Hercynian (about 419 to 299 million years ago) quartz
diorite.
It is suggested that, with decreasing temperature, mineral compositions changed progressively from
tungstate and oxide, to diatomic sulphide, to simple sulphide, to an
antimony sulphosalt mineral, and finally to an
antimonide.
Fluorite occurs at Bairendaba as cubic, cuboctahedral, and cube + dodecahedron crystals, rarely to over 6 cm
in size, primarily in shades of blue-violet but also in shades of blue-green and green. Inclusions of acicular
boulangerite are common
(Minrec 53.347-359).
Fluorite from Bairendaba - Image
At the Shijiang Shan-Shalonggou mine, Hexigten Banner, Chifeng City, Inner Mongolia, China, the mineral deposits occur predominantly in
veins of hydrothermal origin in skarn. Fluorite occurs sparingly as
octahedral crystals to 1 cm at Shijiangshan; they are frequently coated by a
quartz crust. At Shalonggou, however, attractive and large, pale green,
octahedral crystals to 5 cm on edge occur, also coated with a thin quartz crust
(R&M 96.5.401).
Fluorite from Shijiang Shan - Image
At the Yindu Ag-Pb-Zn deposit, Hexigten Banner, Chifeng City, Inner Mongolia, China, fluorite crystals occur as
green or purple, water-clear simple cubes
(AESS).
Fluorite from Yindu - Image
At the Xiefang Mine, Ruijin County, Ganzhou, Jiangxi, China, abundant green, purple or white fluorite occurs,
massive or as sharp octahedrons
(AESS)
Fluorite from Xiefang - Image
At the Dugupi-Ma'anshan Sb ore field, Weishan County, Dali, Yunnan, China, simple cubes of fluorite occur. In reflected light some
of the crystals are a fairly dull, purplish-grey colour. In transmitted light it is apparent that they are translucent, and zoned,
with a very pale mauve interior, and a much darker narrow purple outer zone
(AESS).
Fluorite from the Dugupi-Ma'anshan Sb ore field - Image
At Johanngeorgenstadt, Erzgebirgskreis, Saxony, Germany, fluorite is fairly sparse in the metallic ore veins. In
the pyrite veins of the Gewerken Hoffnung mine, cavity fillings of green
fluorite have been noted. An association of green fluorite with
chlorite, hematite,
actinolite, chalcopyrite and
cassiterite occurred in the Treue Freundschaft mine. In
bismuth - cobalt -
nickel veins, fluorite occurred as a massive
gangue mineral and only rarely as well-formed octahedral crystals to 3 cm. Most
commonly this fluorite is green to pale violet and sometimes colour-zoned, although in the vicinity of
uranium-bearing minerals it is dark purple to black
(MinRec 55.5.597).
At Lettermuckoo Quarry, Kinvarra, Connemara, Galway County, Connacht, Ireland, the minerals are hosted by a
megacrystic pink to grey monzogranite, with occasional
pegmatitic segregations.
Fluorite and quartz are the principal early phases in the paragenetic
sequence. Fluorite was occasionally found as free grown crystals, but on most specimens
calcite was removed using dilute orthophosphoric acid to reveal earlier
fluorite. Crystals vary from medium to very dark purple, and are invariably octahedral. The largest crystals
are up to about 20mm on edge
(JRS 22.40)
Fluorite from the Lettermuckoo Quarry - Image
At the Pili Mine, Saucillo Municipality, Chihuahua, Mexico, fluorite
pseudomorphs after
calcite have been found
(KL p149).
The Navidad Mine, Indé Municipality, Durango, Mexico, exploits four vuggy
fluorite-quartz veins, the
largest of which is 4 to 5 meters wide, and is the source of the abundant
creedite that is found as an
alteration product of the fluorite. The main vein is heavily
brecciated by tectonic movement that followed the
fluorite emplacement, and the creedite then grew within earthy
iron oxides and clays that filled the
breccia voids.
Fluorite from the Navidad mine is naturally dark purple to almost black when found, but turns a pale to medium
green to pinkish purple colour after a few months’ exposure to the sun. The crystals fluoresce deep purple-blue
under long wave UV. The mine has produced thousands of plates of quartz covered
with transparent, usually frosty,
octahedral fluorite crystals to 3 cm on edge
(Minrec 55.6.863).
Fluorite from Navidad - Image
At El Filo vein, Santa Librada, Mapimí Municipality, Durango, Mexico, fluorite is abundant as cubes ranging
from 1 to 20 cm across on an extremely hard, very fine-grained siliceous matrix; many crystals are coated with a
thin siliceous film. Most have a frosty lustre and range in color from nearly colourless to lavender and dark
purple. The colour tends to be more intense in pockets close to the contact with the
shales of the overlying formation. Most of the fluorite
crystals are simple cubes; penetration twins are known but uncommon. Cube faces typically show a rough, stepped,
blocky or parquet appearance, reflecting mosaic growth. Many have shallowly concave faces showing a nearly spiral
pattern between the mosaic domains. Another distinctive growth feature of the faces is irregular, locally developed
colour zoning, with darker purple along the edges of the mosaic domains
(Minrec 55.6.803).
Fluorite from El Filo Vein - Image
At Charcas, Charcas Municipality, San Luis Potosí, Mexico,
the primary minerals are
sphalerite, galena,
chalcopyrite, bornite,
tetrahedrite,
arsenopyrite, pyrite and
silver minerals such as jalpaite,
diaphorite and acanthite. In
the host rock, as metamorphic or alteration minerals, danburite,
datolite, hedenbergite,
epidote, chlorite,
andradite, actinolite
and wollastonite have been reported.
Quartz, calcite and
danburite crystallised during the entire life of the systems, throughout
the intrusive emplacement, metamorphism, and mineralising events. With depth, both
sphalerite and galena decrease
while chalcopyrite increases.
Secondary sulphides formed include
bornite, covellite,
digenite and chalcocite.
Native silver, native gold,
hematite and goethite were
deposited after the sulphides
(Minrec 55.6.727-728).
Fluorits has commonly been observed as late-stage, fine-grained, anhedral interstitial blebs in the sulphide
ores. Well crystallised specimens are extremely rare in old collections, as colourless 2 cm octahedrons. More
recently, in 2020, a very small find produced ochre-brown octahedrons to 1.7 cm in size, on a white
calcite and quartz matrix
(Minrec 55.6.757).
At Zacatecas, Mexico, fluorite occurs as groups of cubic crystals aligned along tubular voids in massive opal
variety
hyalite
(R&M 93.5.409).
Fluorite from Zacatecas - Image
At Trestia, south of Cavnic, Muramures, Romania, chalcedony
pseudomorphs after fluorite have been found
(KL p257).
Chalcedony after Fluorite - Image
At Dalnegorsk, Russia, quartz
pseudomorphs
after fluorite, and calcite
pseudomorphs after fluorite, with a
quartz
coating, have been found
(KL p252, 153).
Fluorite from Dalnegorsk - Image
Berbes, Berbes mining area, Ribadesella, Asturias, Spain is known worldwide for the exceptional quality and
beauty of its fluorite specimens, generally considered to be among the world’s finest.
The fluorite generally occurs as simple cubes, sometimes modified by small dodecahedral faces, and
stepped and mosaic crystal faces are a conspicuous characteristic.
The crystals range in colour from colourless to pale blue and purple. The darkest, most intense purple
colour, usually seen in early-stage fluorite, is thought to be an effect of the highest temperature
and salinity formation conditions in the deposit. The blue to colourless fluorite formed at the
lowest temperatures, and zones with these colours have commonly grown over darker, higher-temperature cores
after marked interruptions in crystal growth caused by changes in the mineralising fluids. Commonly the
colourless to pale blue fluorite crystals overlie other, earlier minerals such as
baryte, sometimes resulting in very showy specimens.
The colour of fluorite may be due to the Frenkel defect, produced by the absence of the fluorine ion,
F-1 from its lattic site; voids in the crystal lattice occur when a fluorine ion has moved to a
normally vacant site other than its own, leaving its own lattice site vacant. Associated energy changes
cause the colour. Another mechanism is the Schottky defect, where two ions of different polarity are missing:
these voids in the crystal lattice can also produce the characteristic purple colour so common in
fluorite. A very dark blue uniform colour throughout the entire fluorite crystal can be caused
by colloidal calcium. In some very specific areas fluorite of a rare, very dark purple, almost black
colour occurs; this colouration is due to trace levels of radioactive elements. Fluorite from Berbes
is generally not fluorescent.
Colour zoning is one of the most attractive features of Berbes fluorite. Changes in the chemistry
and/or temperature of the mineralising fluids are reflected as variations in colour or morphology as the
crystals grow. Nearly every fluorite specimen from this locality shows parallel, concentric phantoms
of a uniform, very dark purple colour
(MinRec 55.1.17-74).
Fluorite from Berbes - Image
From Carn Brea Mine, Pool, Carn Brea, Cornwall, England, specimen BM.1964,R1139 from the Natural History Museum,
London, features colourless transparent cubic crystals of fluorite with dark purple edge zoning scattered over
a matrix of milky quartz crystals with a coating of iron oxide
(RES2 p148).
Fluorite from the Carn Brea Mine - Image
At Wheal Mary Ann, Menheniot, Cornwall, England, UK, quartz
pseudomorphs after fluorite have been found
(R&M 95.3.275). The fluorite is generally pale greenish yellow and fluoresces blue.
Fluorite from Wheal Mary Ann - Image
At the Whiteheaps Mine, Hunstanworth, Coounty Durham, England, UK, colourless to pale purple fluorite
occurs associated with quartz, ankerite
and calcite
(R&M 95.4.335).
Fluorite from Whiteheaps - Image
At the Burtree Pasture mine, Cowshill, Stanhope, County Durham, England, UK, purple fluorite occurs with
quartz, iron carbonates and
calcite
(SY p158, R&M 95.4.318)
Fluorite from the Burtree Pasture Mine - Image
At the Greenlaws Mine, Daddry Shield, Stanhope, County Durham, England, UK, well formed purple and amber coloured
fluorite crystals are found, that fluoresce bright blue
(R&M 95.4.320).
They are almost invariably simple cubes with no additional crystal forms, often water-clear and associated with
galena
(AESS).
Fluorite from Greenlaws - Image
At the Eastgate Quarry, Eastgate, Stanhope, County Durham, England, UK, green fluorite occurs with internal
purple colour zones. Yellow and purple fluorite is also found rarely
(R&M 95.4.322).
Fluorite from Eastgate - Image
At the Blackdene Mine, Ireshopeburn, Stanhope, County Durham, England, UK, purple fluorite occurs with
galena and other sulphides on a quartz
matrix. Yellow and green crystals of fluorite have also been found
(R&M 95.4.317).
Fluorite from the Blackdene Mine - Image
At the Rogerley Mine, Rogerley Quarry, Stanhope, County Durham, England, UK, green, purple and yellow fluorite
has been found, often associated with galena. The best known are the
colour-change crystals which show strong blue highlights in daylight, and are pure green in artificial light
(R&M 95.4.327). These Weardale fluorites contain ten times more rare earth elements than do the non-fluorescent
Derbyshire fluorites. The green colour is thought to be due to the presence of samarium Sm2+ as an
impurity (https://e-rocks.com/blogs/11437/daylight-fluorescence-weardale-green-fluorspar).
Fluorite from the Rogerley Mine - Image
At the Boltsburn Mine, Rookhope, Stanhope, County Durham, England, UK, fluorite is associated with
siderite and calcite.
Epimorphs
of siderite after fluorite have been found here
(SY p150, 158). Deep blue fluorite crystals occur associated with
quartz, calcite
siderite and galena
(R&M 95.4.332).
Fluorite from the Boltsburn Mine - Image
At Frazer's Hush Mine, Rookhope, Stanhope, County Durham, England, UK, purple fluorite occurs with
quartz, galena and
sphalerite
(R&M 95.4.334).
See https://en.wikipedia.org/wiki/Hushing for the meaning of "Hush"
Fluorite from Frazer's Hush - Image
At the Redburn Mine, Rookhope, Stanhope, County Durham, England, UK, pale to medium green fluorite occurs
with calcite, quartz and minor
sulphides. Groups of small purple fluorite have also been found
(R&M 95.4.332).
Fluorite from the Redburn Mine - Image
At the Stotfield Burn Mine, Rookhope, Stanhope, Co. Durham, England, UK, some purple and purple-green fluorite has
been found associated with galena on a
quartz matrix
(R&M 95.4.329).
Fluorite from the Stotfield Burn Mine - Image
At the Heights Mine, Westgate, Stanhope, County Durham, England, UK, magnificent emerald-green fluorite
crystals to 8 cm have been found, and also pale purple to colourless fluorite. Associated minerals include
galena, calcite and
aragonite
(R&M 95.4.322).
Fluorite from the Heights Quarry - Image
At the West Pasture Mine, Stanhope, County Durham, England, UK, fluorite occurs which is apple-green when
recovered, but which fades to purplish grey on exposure to sunlight
(R&M 95.4.325).
It is often associated with quartz, either rock crystal or citrine, and
sometimes fluoresces blue under long wave UV
(AESS).
Fluorite from the West Pasture Mine -
Image
At the Middlehope Burn, Westgate, Weardale, North Pennines, County Durham, England, UK, emerald-green
fluorite occurs on a buff coloured friable matrix
(R&M 95.4.322).
Fluorite from Middlehope - Image
At Rotherhope Fell Mine, Black Burn Area, Alston Moor, Eden, Cumbria, England, UK, fluorite occurs with
calcite and quartz on massive black
limestone
(SY p155). Purple is the most common colour for the fluorite, and some crystals have a surface layer of
amber yellow surrounding a purple core
(R&M 95.4.330).
Fluorite from the Rotherhope Fell Mine - Image
At the Brownley Hill Mine, Nenthead, Alston Moor, Eden, Cumbria, England, UK, good quality specimens of amber coloured
fluorite are found
(R&M 95.4.337).
Fluorite from Brownley Hill - Image
At the Rampgill Mine, Nenthead, Alston Moor, Eden, Cumbria, England, UK, some specimens of small, pale yellow
fluorite crystals with siderite on
quartz have been found
(R&M 95.4.337).
Fluorite from the Rampgill Mine - Image
At the Smallcleugh Mine, Nenthead, Alston Moor, Eden, Cumbria, England, UK, small crystals of yellowish white
fluorite have been found, that fluoresce blue under short wave UV
(AESS).
Fluorite from Smallcleugh - Image
The Hilton Mine, Scordale, Murton, Eden, Cumbria, England, UK, is famous for yellow to amber coloured fluorite,
and is one of the few localities in the region where fluorite is found together with barium minerals, such as
baryte
(R&M 95.4.340).
Fluorite from the Hilton Mine - Image
At Ashover, Derbyshire, England, UK, fluorite is associated with galena and
sphalerite, and sometimes has inclusions of
pyrite
(RES p102, 103).
Fluorite from Ashover - Image
At the Odin mine, Castleton, Derbyshire, England, UK, fluorite is associated with
baryte
(RES p129).
Fluorite from the Odin Mine - Image
At Treak Cliff, Castleton, Derbyshire, England, UK, fluorite is associated with
calcite on
a limestone matrix
(RES p126).
Fluorite from Treak Cliff - Image
At the Crich quarry, Crich, Derbyshire, England, UK, fluorite has been found with
baryte and
calcite
(RES p100).
Fluorite from Crich Quarry - Image
At Eyam, Derbyshire, England, UK, fluorite is associated with calcite,
sphalerite and galena
(RES p117).
Fluorite from Eyam - Image
At Hopping Pipe mine, Matlock, Derbyshire, England, UK, fluorite is often associated with minor
galena or pyromorphite
(RES p72).
At the Millclose Mine, South Darley, Derbyshire Dales District, Derbyshire, England, UK, fluorite occurs with
galena
and sphalerite, with minor pyrite and
baryte, on a limestone matrix.
Fluorite also has
been found associated with hemimorphite
(RES p92, 94).
From Bere Ferrers, West Devon, Devon, England, UK, miniature specimen BM.1964,R1315 from the Natural History Museum,
London, features pale blue to mauve cubic crystals of fluorite on grey metallic dodecahedral crystals of
galena, with a later overgrowth of brassy
chalcopyrite, with minor quartz
matrix
(RES2).
Fluorite from Bere Ferrers - Image
At Croft Quarry, Croft, Blaby, Leicestershire, England, UK, three generations of colourless to pale yellow or pale
greenish blue fluorite
occur, associated with
chalcopyrite, analcime and
calcite. No specimens have been seen where any of the three generations of
fluorite have been
enclosed by later minerals, indicating that the fluorite crystallisation is very late in the paragenesis
(JRS 20.15-16).
At the Elbolton Mine, Elbolton Hill, Thorpe, Craven, North Yorkshire, England, UK, colourless fluorite has
been found with a deep indigo-blue surface layer
(R&M 95.4.343).
Fluorite from Elbolton - Image
At the Coldstones Quarry, Greenhow, High and Low Bishopside, Harrogate, North Yorkshire, England, UK, colourless
to pale yellow fluorite crystals are found, many with a thin blue or purple layer at the surface
(R&M 95.4.343).
Fluorite from Coldstones Quarry - Image
At the Gillheads Mine, Skyreholme, High and Low Bishopside, Harrogate, North Yorkshire, England, UK, fluorite
is typically colourless to pale yellow with a characteristic thin blue/purple layer at the surface
(R&M 95.4.343).
Fluorite from the Gillheads Mine - Image
At the Raygill Level, Hawes, Wensleydale, North Pennines, North Yorkshire, England, UK, colourless, pale yellow
and purple fluorite is associated with baryte and sulphides
(R&M 95.4.342).
Fluorite from the Raygill Level - Image
At the Seata Mine, Aysgarth, Richmondshire, North Yorkshire, England, UK, yellow and amber coloured fluorite
occurs with galena
(R&M 95.4.342).
Fluorite from the Seata Mine - Image
At the Wet Grooves Mine, Carperby-cum-Thoresby, Richmondshire, North Yorkshire, England, UK, colourless to
yellow fluorite occurs with baryte and
calcite
(R&M 95.4.342).
Fluorite from the Wet Grooves Mine - Image
At the Allenheads Mine (Beaumont Mine), Allendale, Northumberland, England, UK, pale lavender crystals of fluorite
associated with sphalerite and
siderite, and purple fluorite associated with
siderite and galena have been found
(R&M 95.4.336).
Fluorite from the Allenheads Mine - Image
At St Peter's Mine, Sparty Lea, Allendale, Northumberland, England, UK, good quality green fluorite has
been found, and also amber and purplish-grey crystals associated with
galena, often with overgrowths of
siderite or quartz
(SY p155, R&M 95.4.337).
Fluorite from St Peter's Mine - Image
At the Hampstead Farm quarry, Chipping Sodbury, South Gloucestershire, England, UK, fluorite has been found on a
calcite matrix
(RES p174).
Fluorite from Chipping Sodbury - Image
At the East Arn Gill mine, Muker, Richmondshire, North Yorkshire, England, UK, fluorite has been found with
included zones of tiny chalcopyrite crystals with
cerussite coated galena crystals
(SY p150).
At the Tockington limestone quarry, near Olveston, South Gloucestershire,
England, UK,
fluorite has been found on calcite in
limestone
(RES p170).
At the Croft quarry, Croft, Leicestershire, fluorite has been found associated with
calcite,
analcime and chalcopyrite
(RES p189).
At Duck Street Quarry, Greenhow, High and Low Bishopside, Harrogate, North Yorkshire, England, UK, fluorite is
found with inclusions of chalcopyrite
(SY p158).
Fluorite from Duck Street Quarry - Image
At the Rorrington mine, Chirbury, Shelve, Shropshire, England, UK, fluorite has been found with
baryte
(RES p287).
At Roar Hill, Ballater, Buchan Grampian, Scotland, UK, lead-bearing vein
mineralisation was exposed during recent work carried out on an unmetalled vehicle track. A small temporary quarry
exposed fluorite-bearing quartz
veins and minor wulfenite in light-coloured granite. At a
second site,
a little further to the west, an oxidised galena-bearing
quartz vein was exposed.
Cavities lined with pyramidal quartz crystals, low temperature
K-feldspar and fluorite were common in veins exposed at the quarry
site. Complete fluorite crystals rarely exceed 5 mm on edge. Many crystals have distinct blue to purple colour
zones, and in a few crystals a dark purple corner is present. Although fluorite appears to be absent at the
track locality, its former presence is betrayed by the presence of cubic
epimorphs; similar
epimorphs occur at the quarry site
(JRS 22.32).
At the Potter-Cramer mine, Vulture Mining District, Maricopa county, Arizona, USA, fluorite is quite common as
octahedral crystals that are milky white, pale blue or dark purple-brown. The milky white and blue fluorite
fluoresces under LW, MW and SW UV, being strongest under LW, and typically europium-activated violet in colour. The
darker-coloured
fluorite does not seem to fluoresce
(R&M 96.1.29).
Fluorite from the Potter-Cramer Mine - Image
At the Keyes Mica Quarries, Orange, Grafton County, New Hampshire, USA, the
pegmatites are beryl-type
rare-element (RE) pegmatites.
The Number 1 mine exposed a pegmatite that shows the most
complex zonation and diverse mineralogy of any of the Keyes
pegmatites. Six zones are distinguished, as follows, proceeding
inward from the margins of the pegmatite:
(1) quartz-muscovite-plagioclase
border zone, 2.5 to 30.5 cm thick
(2) plagioclase-quartz-muscovite
wall zone, 0.3 to 2.4 metres thick
(3) plagioclase-quartz-perthite-biotite
outer intermediate zone, 0.3 to 5.2 metres thick, with lesser muscovite
(4) quartz-plagioclase-muscovite
middle intermediate zone, 15.2 to 61.0 cm thick
(5) perthite-quartz inner intermediate zone, 0.9 to 4.6 meters thick
(6) quartz core, 1.5 to 3.0 metres across
The inner and outer intermediate zones contained perthite crystals up to
1.2 meters in size that were altered to vuggy
albite-muscovite with
fluorapatite crystals. This unit presumably was the source of the
albite, muscovite,
fluorapatite, quartz and other
crystallised minerals found in pieces of vuggy albite
rock on the dumps next to the mine.
The middle intermediate zone produced sheet mica with accessory minerals including
tourmaline, graftonite,
triphylite, vivianite,
pyrite, pyrrhotite, and
beryl crystals to 30.5 cm long and 12.7 cm across.
Fluorite was previously unknown from Grafton County pegmatites,
so it was surprising when a glassy reddish specimen in smoky quartz, collected at
the Keyes No. 1 mine, proved to be fluorite
(R&M 97.4.316-317).
Fluorite from Keyes - Image
At the Galena King Mine, Coyote Canyon, Tijeras Canyon Mining District, Bernalillo county, New Mexico, USA, the deposit
is hosted in granite gneiss.
Fluorite ranges in colour
from a deep ultramarine-blue to a medium blue, and some pockets produced teal blue–green crystals. The blue
fluorite changes colour,
blue under daylight and purple under incandescent light. Crystals to 4 cm typically form as intergrown groups on plates
to 45 cm. Most crystals
are cubes, but a few pockets have produced stepped octahedra. The majority of pockets experienced a
secondary growth of opaque reddish-brown drusy fluorite
covering the internal
blue colour of the primary fluorite. Some of the
fluorite is associated with
slightly altered galena and bladed baryte
groups
(R&M 95.5.406).
Fluorite from the Galena King Mine - Image
At the Highland Mary (Frustration) Mine, Tijeras Canyon District, Bernalillo county, New Mexico, USA, fluorite
veins are hosted in
granite. Fluorite occurs as sea-foam green stepped octahedra or
blue stepped cubes;
simple cubes are uncommon. Crystals are usually smaller than 2.5 cm, but some reach 5 cm on edge. The fluorite may
exhibit a colour
change, appearing bluish in artificial light and more of a green colour in sunlight
(R&M 95.5.407).
Fluorite from the Highland Mary Mine - Image
At the Lucky Bill (Octoroon) Mine, Tijeras Canyon District, Bernalillo county, New Mexico, USA, fluorite occurs as
typical stepped blue cubes partially covered with groups of white baryte blades.
The mine has also produced large plates
of baryte crystals
(R&M 95.5.407-408).
In the Bluewater Area, Zuni Mountains, Cibola county, New Mexico, USA, fluorite forms as layered vein fillings,
and when split open,
plates of teal blue–green botryoids with adamantine luster (unusual for fluorite) are revealed
(R&M 95.5.409).
In the Zuni Mountains, Cibola county, New Mexico, USA, fluorite occurs in veins in
granite
and gneiss at the Prospector’s, Bonnekay, Porter-Mirabal, Grants and Bonita
mines. There is much
variety in colour with many shades of blue, purple, green, yellow, and brown. Most crystals are simple cubes or stepped
cubes to 5 cm, but
some specimens from the Bonnekay mine show stepped purple and green octahedra to 2.5 cm
(R&M 95.5.408-409).
Fluorite from the Zuni Mountains - Image
At the Stevenson-Bennett Mine, Organ Mining District, Organ Mountains, Doña Ana county, New Mexico, USA, the deposit is
much more famous for fine wulfenite but one pocket of fluorite was
discovered near the water level, that
produced lustrous, transparent purple and green modified cubes that are most likely
spinel twins, the
only recorded occurrence of this habit in the state
(R&M 95.5.410).
Fluorite from the Stevenson-Bennett Mine - Image
The Ruby (Hayner) Mine, Modoc District, Doña Ana county, New Mexico, USA, consists of veins and minor replacement bodies
in limestone. Some cubic white and colourless fluorite crystals
to over 2.5 cm on
gossan matrix have been collected here
(R&M 95.5.410).
At Palm Park Mine, Palm Park, Rincon Mining District, Doña Ana county, New Mexico, USA, yellow to amber-colored cubic
fluorite to 5 cm
is sometimes associated with the primary ore minerals
(R&M 95.5.410).
At the Tortugas Mine, Tortugas Mountain District, Doña Ana county, New Mexico, USA, veins are hosted in
limestone. Crystals are generally cubes modified by the dodecahedron
and range in colour from
green to purple to blue, and up to 5 cm across
(R&M 95.5.410).
At Doublestrike Prospects, Bound Ranch District, Grant county, New Mexico, USA, teal blue–green cubes of fluorite
modified by white or
dark purple dodecahedral edges have been found
(R&M 95.5.411).
Fluorite from the Doublestrike Prospects - Image
At Little Rock Mine, Deadman Canyon-California Gulch-Whitewater Canyon Area, Burro Mountains District, Grant county, New
Mexico, USA, veins of
copper mineralisation and minor fluorite are hosted in a monzonite
porphyry that is associated with the nearby copper
porphyry deposit. Plates of dark purple octahedral fluorite crystals
occur on a white
matrix, some plates having a second generation of tiny pale purple crystals preferentially coating faces of the larger
octahedra
(R&M 95.5.412).
At the Lucky Irishman claim, Southwest and Central Burro Mts Area, Burro Mountains District, Grant county, New Mexico,
USA, opaque blue-green
botryoidal fluorite on quartz has been found
(R&M 95.5.412).
At the Pine Canyon deposit, West Burro Mountains, Burro Mountains Mining District, Grant county, New Mexico, USA,
fluorite occurs
commonly as octahedral crystals to approximately 5 cm, typically medium to dark purple with green cores, although a few
specimens show the
inverse. Occasionally, the purple crystals have a colourless or pale green rind. The most distinctive characteristic is
that the crystal faces
are convex. Plates of crystals are common, with many consisting of purple octahedra on a white
quartz
matrix. Nearly all specimens coming out of the ground are coated with a 1–2-mm thick layer of
quartz
(R&M 95.5.412-413).
Fluorite from the Pine Canyon Deposit - Image
At the Tyrone Mine, Tyrone Area, Burro Mountains Mining District, Grant county, New Mexico, USA, medium green octahedral
crystals of
fluorite to 3.2 cm, some on a white quartz matrix, have been found in a
vein of fluorite
in the main pit. The pit has also produced banded carving-grade fluorite with green, purple, and white zonation
(R&M 95.5.414).
Fluorite from the Tyrone Mine - Image
At the Gila Fluorspar Mining District, Grant county, New Mexico, USA, many fine specimens of green and purple octahedral
fluorite have
been found in vein systems hosted in volcanic rocks
(R&M 95.5.414).
Fluorite from the Gila District - Image
At the Foster Mine, Gila Fluorspar District, Grant county, New Mexico, USA, fluorite occurs as plates of green
octahedra to 10 cm, solid
purple octahedra, two-toned green and purple octahedra, and blue and green octahedra. Some crystals have been covered by
a later-stage
quartz. Octahedra can be modified by the cube or can often exhibit a late-stage
growth of cubes
(R&M 95.5.414-415).
At the Last Chance Mine, Gila Fluorspar Mining District, Grant county, New Mexico, USA, fluorite occurs as green
octahedra to 7 cm, often
with a late-stage growth of white fluorite
(R&M 95.5.415).
Fluorite from the Last Chance Mine - Image
At The Cleft, Gila Fluorspar Mining District, Grant county, New Mexico, USA, an outcropping vein of fluorite near
the Last Chance mine
has produced large plates of medium-to-dark green fluorite octahedra to 10 cm on a side, showing the typical
stepped octahedral form
(R&M 95.5.415).
At the Turkey Creek Area, Gila Fluorspar Mining District, Grant county, New Mexico, USA, large, 20-cm, plates of purple
stepped
fluorite octahedra to 2.5 cm have been found, and both green and purple octahedra with crystals to 3 cm
(R&M 95.5.415).
Fluorite from Turkey Creek - Image
At the Watson Mountain Prospect, Gila Fluorspar Mining District, Grant county, New Mexico, USA, fluorite occurs as
green and purple
octahedra to 8 cm. Some of the green crystals are stepped, and all have a tendency to a late-stage growth of white
fluorite
(R&M 95.5.415-416).
Fluorite from Watson Mountain - Image
At the Bluebird Prospects, Gold Hill District, Grant county, New Mexico, USA, fluorite is hosted in veins cutting
granite. Green and purple crystals to 5 cm with cubic, octahedral, and
dodecahedral faces have
been found, and also, in one small pocket, stepped octahedral fluorite crystals modified by the hexoctahedron
(R&M 95.5.416).
At Black Mountain (Polyanna Group), Hidalgo county, New Mexico, USA, fluorite has been found as translucent to
transparent, honey-brown
to chocolate-brown and black-brown cubes to 3 cm, with hexoctahedral modifications
(R&M 95.5.416-417).
At the Gallinas Mountains, Red Cloud District, Lincoln county, New Mexico, USA, fluorite occurs in
breccia zones in sediments and a
porphyritic
trachyte associated with fault zones. Small crystals of deep purple,
stepped cubic
fluorite with dodecahedral modifications colored red by hematite have
been found.
Bastnäsite is also present
(R&M 95.5.417).
Fluorite from the Gallinas Mountains - Image
At the Smokey Bear Quartz Claims, Lincoln county, New Mexico, USA, fluorite is a minor constituent; some fluorite octahedra
have been found in association with the smoky quartz for which the area is famous. The fluorite
forms as medium green octahedra sometimes with purple cores, exceptionally to 5 cm, or as white colloform aggregates
to 2 cm growing on the sides of quartz crystals
(R&M 95.5.417-418).
Fluorite from the Smokey Bear Claims - Image
At Cookes Peak Mining District, Luna county, New Mexico, USA, the deposits are small carbonate replacement deposits in
limestone. Fluorite is one of the
primary gangue minerals and occurs as green
and purple octahedra
(R&M 95.5.418-419).
Fluorite from Cookes Peak District - Image
At Lucky Mine, Fluorite Ridge District, Luna county, New Mexico, USA, most of the deposits are fluorite fissure veins hosted in
monzonite, basalt, and young extrusive rocks,
and there are a couple of small replacement bodies in limestone. Fluorite from the vein
systems is typically cubic; fluorite from the replacement deposits consists of highly modified cubes and octahedra. Crystals are typically
no larger than 6 cm, but some reach 12 cm. Colours include many shades of purple, green, blue, white, and rarely red. Some of the crystals
rest on tiny white quartz crystals
(R&M 95.5.419-420).
At Small Fry prospect, El Rito, El Rito District, Rio Arriba county, New Mexico, USA, rounded crystal aggregates of fluorite are found
in veins in igneous rock and may be associated with small white baryte crystals and
calcite. Individual botryoids are generally no more than 5 cm across and often form colloform groups.
The fluorite is usually medium to dark purple and sometimes is coated with iridescent iron oxide
(R&M 95.5.420).
Fluorite from the Small Fry Prospect - Image
At El Cuervo Butte, Santa Fe county, New Mexico, USA, transparent colorless cubes of fluorite have been found associated with
baryte and minor galena. The cubes reach 2.5 cm and are
modified by the dodecahedron
(R&M 95.5.420).
At the San Pedro Mine, New Placers District, Santa Fe county, New Mexico, USA, fluorite is rare, but it has been found in the
skarn system both as deep purple octahedra to 1.5 cm associated with
hematite and laumontite, and as small grass-green
modified cubes
(R&M 95.5.420).
At the Bohrnstedt Prospect, San Andres Mountains, Sierra county, New Mexico, USA, a military area, purple-black cubes of fluorite
were abundant on the dumps. The crystals, which had been exposed to the sun for more than sixty years, were not much paler in colour than
material found underground. This is one of the very few areas in the state where fluorite is not very photosensitive. Single cubes
reach 7.5 cm and typically grow as groups on plates of small quartz crystals
(R&M 95.5.421).
At the Parker Prospect, Caballo Mountain District, Sierra county, New Mexico, USA, the deposit is hosted in
limestone. Fluorite occurs as green cubic and octahedral crystals to 3.5 cm, some of
them coated with a layer layer of crystalline quartz
(R&M 95.5.421-422).
At the Black Knife group (Prospectors Delight Mine), Cuchillo Negro District, Sierra Cuchillo, Sierra county, New Mexico, USA, small,
white to pale green fluorite crystals to 2 cm dot iron oxide–stained quartz pseudomorphs
after scalenohedral calcite
(R&M 95.5.422).
Fluorite from Black Knife - Image
At the Fairview Mine, Cuchillo Negro District, Sierra Cuchillo, Sierra county, New Mexico, USA, green botryoidal fluorite occurs
covered with large epimorphs of quartz after
rhombohedral calcite
(R&M 95.5.422).
At the Vindicator Mine, Cuchillo Negro District, Sierra Cuchillo, Sierra county, New Mexico, USA, the deposit is a
copper-lead-zinc
garnet skarn system hosted in
limestone adjacent to a contact with a monzonite
sill. Fluorite has been found as mint-green octahedra to 2.5 cm on white quartz, and as green
octahedra to 2.5 cm coated by a thin layer of snow-white albite associated with drusy
quartz and microcrystals of green mottramite
(R&M 95.5.423).
At the Lorraine prospects, Derry District, Sierra county, New Mexico, USA, the deposit is hosted in
limestone. Fluorite has been found as stepped purple and green octahedra to
15 cm, with a later generation of purple-blue fluorite overgrowing select faces of the octahedra. It has also been found as
complex teal blue–green cubes to 4 cm, some associated with brownish-yellow baryte and as transparent,
pale green cubes modified by the dodecahedron
(R&M 95.5.423-424).
Fluorite from the Lorraine Prospects - Image
At the Nakaye Mine, Derry District, Sierra county, New Mexico, USA, limestone beds have been
replaced by fluorite. Associated minerals are colourless to white calcite crystals to 10 cm and
small grey-green baryte crystals to 1 cm. Fluorite from the Nakaye mine is always cubic and can
reach sizes of approximately 15 cm. Most crystals are in the 1–7-cm size range. Colour is varied, ranging from shades of blue, purple, green,
grey, white, brown, and, in rare cases, yellow. The blues and purples tend to be very photosensitive; specimens placed in direct sunlight can
fade to grey within 20–30 minutes. Penetration spinel twins are relatively common
(R&M 95.5.424-425).
Fluorite from Nakaye - Image
At the Lemitar Mountain District, Socorro county, New Mexico, USA, fluorite occurs as gemmy pale green cubes to 4 cm on matrix,
collected from small fluorite veins in granite
(R&M 95.5.425).
Fluorite from the Lemitar Mountain District - Image
At the Blanchard mine, Hansonburg District, Socorro county, New Mexico, USA, fluorite occurs as “Blanchard Blue”, medium to dark blue
cubes to about 2.5 cm scattered and perched on white quartz, also as teal-blue and green cubes to
5.4 cm in quartz matrix. Exceptional blue and purple cubic fluorite to 12 cm showed zoning of
saturated purple cores with a blue rind. The Blanchard mine also produced one of the handful of known penetration twinned
fluorite specimens
(R&M 95.5.425-427).
Fluorite from the Blanchard Mine - Image
At the Linchburg Mine, Magdalena District, Socorro county, New Mexico, USA, there are both carbonate replacement deposits and
skarn deposits where limestone beds have
been replaced adjacent to a rhyolite sill and are also associated with a
monzonite stock. Fluorite occurs as gemmy, highly etched pale purple dodecahedral
crystals atop a first generation of pale green octahedra, and also as of etched mint-green octahedra associated with white
baryte
(R&M 95.5.427).
At Cabresto Creek, Questa District, Taos County, New Mexico, USA, this deposit is a small series of hydrothermal veins with fluorite
and quartz. The fluorite occurs as dark purple crystals with green cores to 2.5 cm, typically
showing multiple-growth octahedra, on a white crystalline quartz matrix
(R&M 95.5.427-428).
At the Red Cloud copper mine, Gallinas Mountains, Red Cloud District, Lincoln County, New Mexico, USA, fluorite
has been found with baryte
(Mindat photo).
Fluorite from the Red Cloud Copper Mine -
Image
At the Penfield Quarry, Penfield, Monroe County, New York, USA, sharp, water-clear cubes of fluorite have been
found.
(MinRec 55.3.356).
Fluorite from the Penfield Quarry - Image
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. Fluorite occurs as small, deep purple crystals of roughly cubic habit,
both in white marble and in serpentine.
Fluorite is also found embedded in tabular phlogopite crystals
(R&M 96.5.437).
Fluorite from Amity - Image
The Purple Diopside Mound, Rose Road, Pitcairn, St. Lawrence county, New York, USA, is situated in
marble. The development of veins of large crystals probably occurred as
a result of fluid penetration from a concurrent intrusion. Many of the minerals of interest to collectors formed during
this primary event, with additional species resulting from the
subsequent alteration of scapolite. There seems to be little, if any,
secondary, late-stage mineralisation present.
Fluorite occurs sparingly as blue prismatic crystals to 4 cm in calcite,
but is more common on the hill above the Purple Diopside Mound associated with purple
diopside in calcite
(R&M 96.6.549).
At Walworth Quarry, Walworth, Wayne County, New York, USA, sharp, water-clear cubes of fluorite have been found.
(MinRec 55.3.356).
Fluorite from the Walworth Quarry - Image
The Stoneco White Rock Quarry, Clay Center, Allen Township, Ottawa county, Ohio, USA, has produced fine cubic
fluorite crystals in shades of yellow and brown, often with interesting phantoms. Fluorite from the
locality is almost invariably fluorescent bluish-white. Although uncommon, twinned tetrahedral orange-red
sphalerite crystals also have been found at Clay Center
(R&M 97.3.277).
Fluorite from the Stoneco Quarry - Image
At the Suever Stone Company quarry, Delphos, Van Wert county, Ohio, USA, fluorite occurs as small, cubic, bicolored yellow and
purple crystals, rarely reaching 5 cm on edge. It is found occasionally in calcite-filled pockets
lined with light brown fluorite that is fluorescent. The main concentrations of fluorite, however, are found as generally brown
cubic crystals, either clear or translucent, in petroleum-containing pockets along with calcite,
dolomite and/or pyrite. Rarely pockets contain
fluorite needles, sheaves, and botryoids. The original needles are frequently covered with small cubes of fluorite of a later
generation. Petroleum is present in all these pockets, and it is thought to be responsible for the brown colour of the fluorite. The
surface layer of the sheaves and botryoids fluoresces to some degree, but the cores and needles show minimal fluorescence. The Suever
fluorites differ from all other Ohio fluorites in that narrow dodecahedral faces {110} commonly occur, bevelling the edges
between faces of the cube. Fluorite crystals here often contain phantoms with various depths of the usual brown colour
(R&M 95.6.505-509, 512-514).
Fluorite from the Suever Stone Company Quarry -
Image
At the Findlay Arch Mineral District spanning parts of Ohio, Michigan and Indiana, USA, fluorite occurs together with
calcite and celestine in Silurian
and Devonian
limestone. These minerals formed in cavities after the rock was laid
down. The
dark brown fluorite
from this locality is coloured by inclusions of bituminous particulates, and fluoresces blue under shortwave radiation
(R&M 93.2.110-133).
Alteration
aegirine, anorthite and
F2 to
albite, fluorite, magnetite
and O2
6NaFe3+Si2O6 + 3CaAl2Si2O8 + 3F2 =
6NaAlSi3O8 + 3CaF2 + 2Fe2+Fe3+2O4 + 2O2
(AM55.126-134)
aegirine, anorthite,
quartz and cryolite to
albite, fluorite, magnetite
and O2
12NaFe3+Si2O6 + 9CaAl2Si2O8 + 21SiO2 +
3Na2NaAlF6 = 21NaAlSi3O8 + 9CaF2 +
4Fe2+Fe3+2O4 + O2
It is only in anorthite-poor siliceous rocks that
cryolite will form in preference to fluorite.
(AM55.126-134)
villiaumite, quartz and
anorthite to
albite and fluorite
2NaF + 4SiO2 + CaAl2Si2O8 = 2NaAlSi3O8 + CaF2
Villiaumite and quartz cannot co-exist
because they combine with
anorthite present in the assemblage to form
albite and fluorite, according to the
above equation
(AM55.126-134).
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