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Formula: PbS
Crystal System: Isometric
Sulphide, galena group
Specific gravity: 7.60 measured, 7.57 calculated
Hardness: 2½
Streak: Lead-grey
Colour: Lead-grey
Solubility: Slightly soluble in hydrochloric and nitric acids
Common impurities: Ag,Cu,Fe,Bi
Environments:
Carbonatites
Metamorphic environments
Hydrothermal environments
Galena is a common primary mineral, found in hypothermal
(high temperature) and mesothermal (moderate temperature)
veins and in contact metamorphic deposits.
In hydrothermal veins it is often associated with
anglesite,
baryte,
bornite,
calcite,
cerussite,
chalcopyrite,
dolomite,
fluorite,
marcasite,
pyrite,
quartz and
sphalerite.
Localities
The Two Mile and Three Mile deposits, Paddy's River, Paddys River District, Australian Capital Territory, Australia,
are skarn deposits at the contact between
granodiorite and volcanic rocks.
Galena is a primary sulphide that occurs with
chalcopyrite in chlorite-rich
material, and intergrown with sphalerite in the
magnetite skarn
at the Two Mile deposit. It also occurs associated with aikinite
(AJM 22.1.37).
At Lingchuan Mine, Lingchuan County, Guilin, Guangxi, China, galena occurs as poorly formed metallic grey crystals
up to 7 mm across on a light grey matrix
(AESS).
Galena from Lingchuan - Image
At Kwun Yum Shan, Yuen Long District, New Territories, Hong Kong, China, the deposit is a hydrothermal deposit which lies
along a fault zone withi altered acid volcanic rocks, consisting mainly of
chlorite, biotite,
sericite and actinolite with
scattered quartz
(Hong Kong Minerals (1991). Peng, C J. Hong Kong Urban Council).
There are several “hot pots” near the top of
the hill. These hot pots were thought to be outlets of warm and moist air, which is heated below the ground and ejected
through fissures and cracks in the rocks. The rocks here, however, are more likely to be
pyroclastic in nature. Mineral veins of quartz,
pyrite and galena can be identified, and
large crystals of quartz are present in the rock. The Hong Kong Geological Survey
has now re-interpreted the rock as an
altered intrusive rhyolitic
hyaloclastite. It is possible that the outcrop marks a vent feeder
of volcanic rocks
(Geological Society of Hong Kong newsletter 14.1).
At the Lin Ma Hang mine, North District, New Territories, Hong Kong, China, the
lead-zinc deposit is a hydrothermal
deposit which lies along a fault zone within altered acid volcanic rocks, consisting mainly of
chlorite, biotite,
sericite and actinolite, with
scattered quartz.
(Hong Kong Minerals (1991). Peng, C J. Hong Kong Urban Council)
The mineralisation consists of a series of fissure vein deposits varying from a few mm to several metres on width. The
initial vein filling was coarse milky quartz. this was followed by an intrusion
of fine-grained quartz carrying the metallic minerals,
galena, pyrite,
sphalerite and chalcopyrite,
in order of abundance
(Geological Society of Hong Kong Newsletter, 9.4.3-27).
Silver-bearing galena occurs as
cleaveable granular masses
(Hong Kong Minerals (1991). Peng, C J. Hong Kong Urban Council).
Galena from Lin Ma Hang - Image
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.
Galena has been reported to occur in quartz veins cutting the
skarn
(Hong Kong Minerals (1991). Peng, C J. Hong Kong Urban Council)
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)
At Chuen Lung, Tsuen Wan District, New Territories, Hong Kong, China, in fissure veins in
granite rocks in a small stream near Chuen Lung,
silver-bearing galena occurs associated
with massive granular amber coloured sphalerite,
chalcopyrite,
pyrite and pyrrhotite
(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).
Silver-bearing galena occurs here
(Hong Kong Minerals (1991). Peng, C J. Hong Kong Urban Council).
At Huangshaping Mine, Huangshaping Pb-Zn-polymetallic ore field, Guiyang County, Chenzhou, Hunan, China, grey, metallic
galena occurs associated with brassy yellow chalcopyrite
(AESS).
Galena from Huangshaping - Image
At Chashan Mine, Xianghualing Sn-polymetallic ore field, Linwu County, Chenzhou, Hunan, China, massive dark grey, metallic,
crystalline galena occurs with brassy yellow chalcopyrite
(AESS).
Galena from Chashan - Image
At Xianghualing Mine, Xianghualing Sn-polymetallic ore field, Linwu County, Chenzhou, Hunan, China, galena is found as
small grey cubic crystals with brassy yellow chalcopyrite and minor
bornite
(AESS).
At the Manaoshan Mine, Dongpo ore field, Suxian District, Chenzhou, Hunan, China, galena occurs as bright silvery bands in
a white crystalline matrix
(AESS).
Galena from Manaoshan - Image
At the Dongpo ore field, Suxian District, Chenzhou, Hunan, China, galena occurs with
sphalerite and quartz
(AESS, Mindat photos).
Galena from Dongpo - Image
At the Yaogangxian Mine, Yaogangxian W-Sn ore field, Yizhang County, Chenzhou, Hunan, China, galena occurs with
crystalline quartz
(AESS).
Galena from Yaogangxian - 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.
Brilliantly lustrous cubic crystals of galena to 2 cm were found with large
pyrrhotite crystals and purple
fluorite crystals in an exceptional pocket in 2019
(Minrec 53.347-359).
At the Shijiang Shan-Shalonggou mining area, Inner Mongolia, China, the mineral deposits occur predominantly in
veins of hydrothermal origin in skarn. Galena is rarely found in
association with borate specimens as small grains. One specimen shows an unusual
cuboidal crystal of galena, 2 cm long, with roweite and minor
olshanskyite. This crystal is probably of
secondary origin
(R&M 96.5.401).
At Ganluo County, Liangshan Yi, Sichuan, China, Galena has been found as an interlocking aggregate of dark grey,
metallic crystals
(AESS).
Galena from Ganluo County - Image
At Poullaouen, France, galena has been found as alteration pseudomorphs
after pyromorphite
(KL p129).
Galena from Poullaouen - Image
At Johanngeorgenstadt, Erzgebirgskreis, Saxony, Germany, galena was found in ore veins and less commonly in the
gravel beds intercalated with phyllite. In massive form, it is commonly
intergrown with quartz. Well crystallized galena in cuboctahedrons to
nearly a centimetre, modified on the edges by dodecahedron faces, was found in cavities and clefts. Large concentrations
of galena were met with in the Gnade Gottes, Treue Freundschaft, Neujahr Maassen and Gottes Segen mines.
Associated minerals included sphalerite,
chalcopyrite, pyrite,
pitchblende, cobalt -
nickel ores, silver ores and
native arsenic. Very rarely there were finds of galena
pseudomorphs after
pyromorphite
(MinRec 55.5.597-598).
Galena from Johanngeorgenstadt -
Image
At the Old Hope of God pit, Freiberg, Saxony, Germany, acanthite has been found as
pseudomorphs after galena
(KL p126).
At the Nakhlak Mine, Anarak District, Nain County, Isfahan Province, Iran, epigenetic (formed later than the
surrounding or underlying rock formation) vein deposits and metasomatic replacement bodies are hosted by a chalky
Upper Cretaceous (100.5 to 66 million years ago) limestone. The
limestone underwent
dolomitisation prior to sulphide mineralisation. The principal
primary ore mineral is
galena, associated with minor or trace amounts of
sphalerite, tetrahedrite
-tennantite, pyrite and
chalcopyrite as inclusions. The main
secondary ore mineral is
cerussite, sometimes associated with minor amounts of
anglesite, plattnerite,
wulfenite, minium,
mimetite, covellite,
chalcanthite, malachite and
goethite. Many trace elements are present in the
primary galena, but
most notably it is rich in silver and
antimony and poor in bismuth.
Galena forms 99% of Nakhlak sulphide minerals, usually as massive material, but also occasionally as crystals
ranging in size from 0.2 to 2 mm but in rare cases up to 1 cm. The economically valuable
silver content is the result of solid-solution isomorphous substitution for
lead involving a coupled substitution with
antimony or bismuth to maintain
charge balance. This mechanism may also account for high copper,
arsenic and antimony contents.
Inclusions of other sulphides are common as well
(Minrec 54.3.383-408).
At Tsumeb, Oshikoto region, Namibia, galena has been found associated with
enargite
(R&M 93.6.544).
Galena from Tsumeb - Image
At Berg Aukas, Grootfontein, Otjozondjupa Region, Namibia, galena occurs most commonly as intergrowths with
sphalerite. It is found in veins with
smithsonite, willemite and
cerussite. Galena from this locality contains traces of
antimony and manganese
(R&M 96.2.131-132).
The paragenetic sequence for the sulphides is proposed to be pyrite (oldest) -
bornite - chalcopyrite -
tennantite - sphalerite -
galena - enargite -
germanite - renierite -
tetrahedrite - jordanite
(youngest)
(R&M 96.2.131-132).
At the Witwatersrand goldfield, South Africa, attractive specimens of galena have been found at several
gold mines
in the Carletonville and Welkom goldfiends
(R&M 96.4.326).
At the Geduld Mine, Welkom, Lejweleputswa District, Free State, South Africa, well-formed cubic, cuboctahedral and
distorted
cubic galena crystals, some associated with sphalerite and/or
pyrrhotite were found
(R&M 96.4.326).
At the Kusasalethu Mine, Carletonville, Western Sector, Far West Rand, West Rand District Municipality, Gauteng, South
Africa,
crystallographically more complex galena specimens were collected. Some galena displays highly
distorted
forms with elongated and/or flattened shapes caused by constricted growth. With a few exceptions, the lustre is
rather
dull with crystal surfaces being finely pitted. Associated minerals include
quartz,
baryte and pyrobitumen
(R&M 96.4.326).
At the Mariquita Mine (Sultana Mine), Usagre, Badajoz, Extremadura, Spain, galena is found as small masses
with typical cubic cleavage, as an accessory mineral in the
primary mineralisation, associated with
tetrahedrite, chalcopyrite
and cinnabar. It is not very abundant
(MinRec 55.4.502).
At Alderley Edge, Cheshire, England, UK, copper mineralised solutions
percolated through porous
sandstone and deposited
barium, cobalt,
copper,
lead,
vanadium and zinc minerals between the
sand grains.
Anhydrite formed as cement in permeable rocks, then
baryte was deposited, followed by pyrite,
chalcopyrite, sphalerite and
galena. Subsequently a second generation of baryte and iron-rich
calcite followed. These minerals crystallised from highly saline, sulphate-rich
brines, at a temperature of 50 to 60o C. About 65 million years ago the deposit was uplifted, and oxygenated
ground water oxidised original sulphide minerals. Galena was oxidised to
cerussite,
anglesite and pyromorphite
(RES pps 49-50). A sample of galena has been found associated with
copper
and pyromorphite
(RES p54).
At Force Crag Mine, Coledale, Above Derwent, Allerdale, Cumbria, England, UK, a specimen has been found of galena
with a dense coating of cerussite formed into ingrown crystals in a vug
(AESS)
Galena from Force Crag - Image
At Old Brandley Mine, Catbells, Keswick, Allerdale, Cumbria, England, UK, a specimen has been found of a
crystalline
quartz matrix with a dense coverage of galena crystals showing
advanced
stages of alteration to cerussite
(AESS)
Galena from the Old Brandley Mine - Image
At the Clargillhead vein, Garrigill, Alston Moor, Eden, Cumbria, England, UK, galena is the dominant
opaque phase and mainly forms euhedral and subhedral crystals up to a few millimetres in diameter. Whereas
some of the galena is inclusion-free, some carries inclusions of other sulphide and sulphosalt minerals.
The most abundant of these is bournonite. Inclusions of
chalcopyrite, pyrite,
ullmannite and
sphalerite are common inclusions in the galena, with much
rarer grains of gersdorffite and
boulangerite. Galena is locally intergrown with
chalcopyrite
(JRS 23.49).
At Nenthead, Alston Moor, Eden, Cumbria, England, UK, galena is associated with
sphalerite and ankerite
(SY p161).
At the Brownley Hill Mine, Nenthead, Alston Moor, Eden, Cumbria, England, UK, a specimen has been found, 5.3 cm across,
with dark grey opaque crystals of galena to 1 cm across, with a brilliant metallic lustre. There are also very
dark brown crystals of sphalerite up to 5 mm across, with a resinous lustre.
There is little or no matrix
(AESS).
Galena from Brownley Hill - Image
At the Smallcleugh Mine, Nenthead, Alston Moor, Eden, Cumbria, England, UK, galena occurs with
quartz, ankerite,
dolomite and fluorite. In some old
specimens cubic crystals of galena reach 2.6 cm on edge
(AESS).
Galena from Smallcleugh - Image
At the Murton Mine, Scordale, Murton, Eden, Cumbria, England, UK, a specimen of galena has been found from this
little known locality, consisting of matrix with galena and quartz
crystals coated in small, but very lustrous green micro mimetite crystals and
some brighter green annabergite
(AESS).
Galena from the Murton Mine - Image
At the Wakebridge Mine, Crich, Amber Valley, Derbyshire, England, UK, galena is associated with
baryte and
calcite
(RES p129).
The Sunnyside Deposit, Whitwell, Bolsover District, Derbyshire, England, UK, is hosted by late Permian (256 to 248
million years ago) dolostone that lies above a thick sequence of
Carboniferous (354 to 290 million years ago) Coal Measures sediments.
When a 1970 collection was re-examined, only two galena specimens remained. In both cases, galena
occurs as idiomorphic masses in a red baryte
vein-breccia surrounding angular clasts of saccharoidal
dolostone. On one specimen, crude pitted cuboctahedral
galena crystals up to 11 mm across project into a small cavity
(JRS 24.37-59).
At the Whitwell Quarry, Whitwell, Bolsover District, Derbyshire, England, UK, galena is associated with
baryte
(RES p138).
At Eyam, Derbyshire Dales District, Derbyshire, England, UK, galena is associated with fluorite,
calcite and sphalerite
(RES p117, 118).
Galena from Eyam - Image
At the Millclose Mine, South Darley, Derbyshire Dales District, Derbyshire, England, UK, galena is associated with
calcite,
sphalerite, fluorite,
pyrite and baryte, on
limestone
(RES p92, 94).
At the Odin Mine, Castleton, High Peak, Derbyshire, England, UK, galena occurs in
limestone
(RES p102).
At the Gregory Mine, Overton Hall, Ashover, North East Derbyshire District, Derbyshire, England, UK, galena is associated with
fluorite
(RES p102).
Galena from the Gregory Mine - Image
At Croft Quarry, Croft, Blaby, Leicestershire, England, UK, galena occurs as dull grey cubes to 2 mm on edge with
analcime, marcasite,
calcite and, occasionally,
cerussite. It also occurs
as groups of cubo-octahedral crystals to 2 mm that may be associated with
chalcopyrite,
analcime and calcite
(JRS 20.17).
At the Breedon quarry, Breedon on the Hill, Leicestershire, England, UK, galena is associated with
cerussite, baryte and
wulfenite
(RES p202, 203).
At Cloud Hill quarry, Breedon on the Hill, Leicestershire, England, UK, galena is associated with
dolomite and calcite
(RES p204).
Galena from the Cloud Hill Quarry - Image
At the Ticklow Lane mine, Shepshed, Leicestershire, England, UK, galena is associated with
cerussite
(RES p225).
At Earl Ferrers mine, Staunton Harold, Leicestershire, England, UK, galena is associated with
calcite, dolomite,
sphalerite, chalcopyrite and
baryte, in dolomitised
limestone
(RES p217-222).
At Barrasford Quarry, Chollerton, Northumberland, England, UK, small masses of galena up to 20 mm across,
accompanied by
sphalerite, have been found in
quartz–calcite veins; small amounts of
pyrite,
pyrrhotite and traces of
chalcopyrite have also been
seen in these veins
(JRS 21.9).
At Divethill Quarry, Little Bavington, Northumberland, England, UK, galena crystals up to 10 mm across have been
seen in a narrow
vein of calcite
(JRS 21.9).
At the Bog mine, Callow Hill-Bog district, Shropshire, England, UK, galena is associated with
fluorite,
sphalerite and calcite
(RES p279).
At Snailbeach mine, Callow Hill-Bog district, Shropshire, England, UK, galena is associated with
quartz and
calcite
(RES p272, 275).
At the Callow Hill quarry, Pontesbury, Callow Hill-Bog district, Shropshire, England, UK, galena is associated
with
pyrite
(RES p290).
Galena from Callow Hill - Image
At the Tankerville mine, Hope-Shelve district, Shropshire, England, UK, galena is associated with
calcite
(RES p281).
At the Shadwell quarry, Much Wenlock, Shropshire, England, UK, galena is associated with
calcite
in limestone
(RES p296).
At the Ecton mine, Staffordshire, England, UK, galena is associated with
chalcopyrite,
sphalerite and calcite
(RES p306).
Galena from Ecton - Image
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.
Galena occurs as altered crystals in vein quartz at the track exposure,
commonly overgrown by cerussite and possibly
anglesite and may be associated with lime-green crustose
pyromorphite, brown spheroidal
mimetite and drusy orange
wulfenite
(JRS 22.33).
At the Sweetwater mine, Missouri, USA, chalcopyrite
pseudomorphs after galena have been found
(KL p131).
Galena from the Sweetwater Mine - Image
At the PC Mine, Cataract Mining District, Jefferson county, Montana, USA, galena was found as cubes and octahedra
to 12 cm coated with a thin grey layer of anglesite and containing trace
amounts of silver. Sulphides are not common in
the deposit, but a few pockets near the level of the creek did have sulphides of surprising size
(R&M 96.6.494).
Galena from the PC Mine - Image
At Cookes Peak mining district, Luna county, New Mexico, USA, galena is the primary
lead sulphide mineral present, but
most of the galena occurs in replacement pods hosted by
limestone,
where oxidation has not occurred. Some specimens have been found where the galena has been partially altered to
cerussite and coated with microcrystalline
wulfenite
(R&M 94.3.232-233).
Galena from Cookes Peak - Image
Alteration
In the oxidation zone of epithermal (low temperature) veins initially
pyrite is oxidised to ferric sulphate, which
is itself a strong oxidising agent. The ferric sulphate then reacts with galena to form
anglesite.
Oxidation of pyrite:
pyrite + oxygen + H2O → ferrous sulphate + sulphuric acid
FeS2 + 7O + H2O → Fe2+SO4 + H2SO4
The ferrous (divalent) sulphate readily oxidises to ferric (trivalent) sulphate and ferric hydroxide
ferrous sulphate + oxygen + H2O → ferric sulphate + ferric hydroxide
6Fe2+SO4 + 3O + 3H2O → 2Fe3+2(SO4)3 +
2Fe3+(OH)3
galena, ferric sulphate, water and oxygen to anglesite, ferrous sulphate
and sulphuric acid
PbS + Fe3+2(SO4)3 + H2O + 3O → PbSO4
+ 2Fe2+SO4 + H2SO4
Galena is oxidised to anglesite and ferric iron is reduced to ferrous
iron
(AMU b3-3.7).
Galena may also dissolve in carbonic acid from percolating rainwater to form hydrogen sulphide, which is then
oxidised to
form anglesite
(KB).
galena and carbonic acid to Pb2+, hydrogen sulphide and HCO3-
PbS + 2H2CO3 → Pb2+ + H2S + 2HCO3-
(KB)
then hydrogen sulphide, oxygen, Pb2+ and HCO3- to
anglesite and carbonic acid
H2S + 2O2 + Pb2+ + 2HCO3- → PbSO4 +
2H2CO3
(KB)
galena and oxygen to anglesite
In air, at outcrops of galena,
PbS + 2O2 → PbSO4
At ordinary temperatures the equilibrium is displaced far to the right, and the apparent stability of galena is a
result of the slowness of the oxidation
(KB).
In the oxidation zone of epithermal veins galena alters to anglesite or
cerussite depending on the acidity.
Cerussite
forms in more basic (alkaline) environments than anglesite.
During the progressive weathering of assemblages of supergene lead minerals
anglesite disappears first, then
cerussite, and finally only
pyromorphite, mimetite and
vanadinite persist
(AM 100:1584-1594).
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