UNIVERSITY OF SOUTH ALABAMA
GY 302: Crystallography &
Mineralogy
Lecture 9: Sulfides
Instructor: Dr. Douglas Haywick
Native Elements
Copper
Metals Gold
Silver
Platinum
Arsenic
Semi-metals Antimony
Bismuth
Tellurium
Sulfur
Non-metals Graphite
Diamond
Cu
Au*
Ag*
Pt*
As
Sb
Bi
Te
S
C*
C*
Isometric
Isometric
Isometric
Isometric
Hexagonal
Hexagonal
Hexagonal
Trigonal
Orthorhombic
Hexagonal
Isometric
* primary production from native elements
Metallic Native Elements
Gold (Au)
Crystal: Isometric
─
Pt. Group: 4/m32/m
Habit: octahedral,
dendritic
SG: 15.6-19.3 (depending on Ag content)
H: 2.5-3*
L: metallic
Col: gold-yellow
Str: gold-yellow
Clev: none
Optical: Opaque
Name Derivation: Anglo Saxon, of uncertain origin.
http://www.rocksandgems.info
Metallic Native Elements
Resources: a concentration of a material useful to humanity (water, food,
minerals)
Geological Resources: all materials (mineral and energy) including those only
surmised to exist, that have present or anticipated future value and which can
be extracted from the Earth via economically feasible methods ($$$) (i.e., gold,
diamonds, coal, oil, natural gas, water)
Reserve Base: The in-place demonstrated (measured+indicated) amount of a
resource that can be extracted via current mining and production techniques
(currently economical + marginal +/- subeconomical). Equivalent to the old
“geological reserve” definition.
Reserve (current): That part of the reserve base that could be economically
extracted today
Production: refined metal produced per year (metric tons)
Metallic Native Elements
Gold (production, reserves in tonnes*)
Production: refined metal produced per year (metric tons)
*1 metric ton (tonne) = 1000 kg = 32,150.7 troy ounces
http://minerals.usgs.gov/minerals/pubs/mcs/2015/mcs2015.pdf
Metallic Native Elements
Gold (US data)
2015 Mineral Commodity Summaries. USGS
Metallic Native Elements
Silver (Ag)
Crystal: Isometric
─
Pt. Group: 4/m32/m
Habit: massive, acicular
SG: 10.1-10.5
H: 2.5-3
L: metallic
Col: silver-white
Str: silver-white
Clev: none
Optical: Opaque
http://webmineral.com/specimens/picshow.php?id=1060
Name: Derivation: Anglo Saxon, of uncertain origin.
Metallic Native Elements
Platinum Group (Pt, Ir, Pa, Rh, Ru, Os,)
Crystal: Isometric
─
Pt. Group: 4/m32/m
Habit: massive, acicular
SG: 21.47
H: 4-4.5
L: metallic
Col: gray-silver
Str: gray-silver
Clev: none
Optical: opaque
Name Derivation: Spanish, platina = "silver."
Non-metallic Native Elements
Graphite (C)
Crystal: Hexagonal
Pt. Group: 6/m 2/m 2/m
Habit: platey, massive
SG: 2.1-2.2
H: 1-2
L: submetallic
Col: lead-gray, black
Str: black
Clev: perfect basal {001}
Optical: opaque
Name derivation: From the Greek, graphein, "to write
Gold
Gold precipitation depends on:
• Temperature
• Pressure
• pH
• Cl- concentration of
hydrothermal solutions
• H2S fugacity*
*pressure of an ideal gas which has the
same chemical potential as the real gas.
http://www.mawsonresources.com
Gold
Gold is usually transported as [AuCl2-] in systems hotter
than 400 C.
[Au(HS)2-] is the dominant ion complex at lower
temperatures
Maximum solubility
occurs near the
H2S-HS--SO42equilibrium point
Gold
Gold is usually transported as [AuCl2-] in systems hotter
than 400 C.
[Au(HS)2-] is the dominant ion complex at lower
temperatures
AU dissolution
(Zhu, An and Tan, 2011)
Gold
Precipitation of gold usually occurs following reduction in
oxygen fugacity (Au-S complexes break down leading to
precipitation of other sulfides like pyrite and precipitation of
gold):
AU precipitation
(Zhu, An and Tan, 2011)
Gold
Gold is largely produced through hydrothermal
precipitation
http://gsc.nrcan.gc.ca/mindep/synth_dep/gold/vms/pdf/deposit_synthesis.gold_vms.dube.pdf
Gold
Golden Giant Mine (Newmont)
Gold Extraction
Cyanide Leeching Method
4Auo + 8CN- + O2 + 2H2O = 4Au(CN)2- + 4OH-
http://www.daa.com.au/uploads/RTEmagicC_mm_leachfeed.jpg.jpg
Gold Extraction
Heap Cyanide
Leeching
Method
Non-metallic Native Elements
Diamond (C)
Crystal: Isometric
─
Pt. Group: 4/m32/m
Habit: octahedral, twinned
SG: 3.5
H: 10
L: adamantine
Col: colorless, rare blue,
red, yellow
Str: n/a
Optical: isotropic, n=2.419
Clev: perfect {111}
Diamonds
Diamond
Phase diagram
http://members.tm.net/lapointe/Carbon_Phase_Diagram.gif
Diamonds
Diamond
Kimberlite Pipes
http://www.earth.ox.ac.uk/~oesis/field/medium/kimberlite.jpg
http://www.kimcordiamonds.com/formation.php
Diamonds
Diamond
Kimberlite Pipes
http://gsc.nrcan.gc.ca/diamonds/kirkland/images/c14_3.jpg
http://www.kimcordiamonds.com/formation.php
Diamonds
Diamonds
http://gsc.nrcan.gc.ca/mindep/synth_prov/slave/pdf/regional_synthesis.slave.bleeker.pdf
Today’s Agenda
Sulfides and Sulfosalts
1.
2.
Properties of select sulfides/sulfosalts
Occurrences and Associations
Featured minerals: Cu-sulfides
Sulfides,
Sulfosalts
and
Arsenides
Sulfides, Sulfosalts and Arsenides
Pb-ore
Mineral
Formula
System
Argentite
Arsenopyrite
Bornite
Boulangerite
Chalcocite
Chalcopyrite
Cinnabar
Cobaltite
Covellite
Domeykite
Digenite
Enargite
Galena
Jamsonite
Marcasite
Millerite
Molybdenite
Nickeline/Niccolite
Orpiment
Pararamnelsbergite
Pyrite
Pyrrhotite
Realgar
Skutterudite/smaltite
Sphalerite
Stibnite
Tetrahedrite
Ag2S
FeAsS
Cu5FeS4
Pb5Sb4S11
Cu2S
CuFeS2
HgS
CoAsS
CuS
Cu3As
Cu9S5
Cu3AsS4
PbS
Pb4FeSb6S14
FeS2
NiS
MoS2
NiAs
As2S3
NiAs2
FeS2
Fe(1-x)S
AsS
(Co,Ni)As2-3/(Co,Ni)As3x
ZnS
Sb2S3
(Cu, Fe)12Sb4S13
Isometric
Monoclinic
Tetragonal/ Isometric
Orthorhombic
Monoclinic
Tetragonal
Hexagonal
Isometric
Hexagonal
Isometric
Hexagonal (trigonal)
Orthorhombic
Isometric
Monoclinic
Orthorhombic
Hexagonal
Hexagonal
Hexagonal
Monoclinic (combined with realgar)
Orthorhombic
Isometric
Variable
Monoclinic (combined with orpiment)
Isometric
Isometric
Orthorhombic
Isometric
Sulfides, Sulfosalts and Arsenides
Zn-ore
Mineral
Formula
System
Argentite
Arsenopyrite
Bornite
Boulangerite
Chalcocite
Chalcopyrite
Cinnabar
Cobaltite
Covellite
Domeykite
Digenite
Enargite
Galena
Jamsonite
Marcasite
Millerite
Molybdenite
Nickeline/Niccolite
Orpiment
Pararamnelsbergite
Pyrite
Pyrrhotite
Realgar
Skutterudite/smaltite
Sphalerite
Stibnite
Tetrahedrite
Ag2S
FeAsS
Cu5FeS4
Pb5Sb4S11
Cu2S
CuFeS2
HgS
CoAsS
CuS
Cu3As
Cu9S5
Cu3AsS4
PbS
Pb4FeSb6S14
FeS2
NiS
MoS2
NiAs
As2S3
NiAs2
FeS2
Fe(1-x)S
AsS
(Co,Ni)As2-3/(Co,Ni)As3x
ZnS
Sb2S3
(Cu, Fe)12Sb4S13
Isometric
Monoclinic
Tetragonal/ Isometric
Orthorhombic
Monoclinic
Tetragonal
Hexagonal
Isometric
Hexagonal
Isometric
Hexagonal (trigonal)
Orthorhombic
Isometric
Monoclinic
Orthorhombic
Hexagonal
Hexagonal
Hexagonal
Monoclinic (combined with realgar)
Orthorhombic
Isometric
Variable
Monoclinic (combined with orpiment)
Isometric
Isometric
Orthorhombic
Isometric
Sulfides, Sulfosalts and Arsenides
Mo-ore
Mineral
Formula
System
Argentite
Arsenopyrite
Bornite
Boulangerite
Chalcocite
Chalcopyrite
Cinnabar
Cobaltite
Covellite
Domeykite
Digenite
Enargite
Galena
Jamsonite
Marcasite
Millerite
Molybdenite
Nickeline/Niccolite
Orpiment
Pararamnelsbergite
Pyrite
Pyrrhotite
Realgar
Skutterudite/smaltite
Sphalerite
Stibnite
Tetrahedrite
Ag2S
FeAsS
Cu5FeS4
Pb5Sb4S11
Cu2S
CuFeS2
HgS
CoAsS
CuS
Cu3As
Cu9S5
Cu3AsS4
PbS
Pb4FeSb6S14
FeS2
NiS
MoS2
NiAs
As2S3
NiAs2
FeS2
Fe(1-x)S
AsS
(Co,Ni)As2-3/(Co,Ni)As3x
ZnS
Sb2S3
(Cu, Fe)12Sb4S13
Isometric
Monoclinic
Tetragonal/ Isometric
Orthorhombic
Monoclinic
Tetragonal
Hexagonal
Isometric
Hexagonal
Isometric
Hexagonal (trigonal)
Orthorhombic
Isometric
Monoclinic
Orthorhombic
Hexagonal
Hexagonal
Hexagonal
Monoclinic (combined with realgar)
Orthorhombic
Isometric
Variable
Monoclinic (combined with orpiment)
Isometric
Isometric
Orthorhombic
Isometric
Sulfides, Sulfosalts and Arsenides
Ag-ore
Mineral
Formula
System
Argentite
Arsenopyrite
Bornite
Boulangerite
Chalcocite
Chalcopyrite
Cinnabar
Cobaltite
Covellite
Domeykite
Digenite
Enargite
Galena
Jamsonite
Marcasite
Millerite
Molybdenite
Nickeline/Niccolite
Orpiment
Pararamnelsbergite
Pyrite
Pyrrhotite
Realgar
Skutterudite/smaltite
Sphalerite
Stibnite
Tetrahedrite
Ag2S
FeAsS
Cu5FeS4
Pb5Sb4S11
Cu2S
CuFeS2
HgS
CoAsS
CuS
Cu3As
Cu9S5
Cu3AsS4
PbS
Pb4FeSb6S14
FeS2
NiS
MoS2
NiAs
As2S3
NiAs2
FeS2
Fe(1-x)S
AsS
(Co,Ni)As2-3/(Co,Ni)As3x
ZnS
Sb2S3
(Cu, Fe)12Sb4S13
Isometric
Monoclinic
Tetragonal/ Isometric
Orthorhombic
Monoclinic
Tetragonal
Hexagonal
Isometric
Hexagonal
Isometric
Hexagonal (trigonal)
Orthorhombic
Isometric
Monoclinic
Orthorhombic
Hexagonal
Hexagonal
Hexagonal
Monoclinic (combined with realgar)
Orthorhombic
Isometric
Variable
Monoclinic (combined with orpiment)
Isometric
Isometric
Orthorhombic
Isometric
Sulfides, Sulfosalts and Arsenides
Hg-ore
Mineral
Formula
System
Argentite
Arsenopyrite
Bornite
Boulangerite
Chalcocite
Chalcopyrite
Cinnabar
Cobaltite
Covellite
Domeykite
Digenite
Enargite
Galena
Jamsonite
Marcasite
Millerite
Molybdenite
Nickeline/Niccolite
Orpiment
Pararamnelsbergite
Pyrite
Pyrrhotite
Realgar
Skutterudite/smaltite
Sphalerite
Stibnite
Tetrahedrite
Ag2S
FeAsS
Cu5FeS4
Pb5Sb4S11
Cu2S
CuFeS2
HgS
CoAsS
CuS
Cu3As
Cu9S5
Cu3AsS4
PbS
Pb4FeSb6S14
FeS2
NiS
MoS2
NiAs
As2S3
NiAs2
FeS2
Fe(1-x)S
AsS
(Co,Ni)As2-3/(Co,Ni)As3x
ZnS
Sb2S3
(Cu, Fe)12Sb4S13
Isometric
Monoclinic
Tetragonal/ Isometric
Orthorhombic
Monoclinic
Tetragonal
Hexagonal
Isometric
Hexagonal
Isometric
Hexagonal (trigonal)
Orthorhombic
Isometric
Monoclinic
Orthorhombic
Hexagonal
Hexagonal
Hexagonal
Monoclinic (combined with realgar)
Orthorhombic
Isometric
Variable
Monoclinic (combined with orpiment)
Isometric
Isometric
Orthorhombic
Isometric
Sulfides, Sulfosalts and Arsenides
Co-ore
Mineral
Formula
System
Argentite
Arsenopyrite
Bornite
Boulangerite
Chalcocite
Chalcopyrite
Cinnabar
Cobaltite
Covellite
Domeykite
Digenite
Enargite
Galena
Jamsonite
Marcasite
Millerite
Molybdenite
Nickeline/Niccolite
Orpiment
Pararamnelsbergite
Pyrite
Pyrrhotite
Realgar
Skutterudite/smaltite
Sphalerite
Stibnite
Tetrahedrite
Ag2S
FeAsS
Cu5FeS4
Pb5Sb4S11
Cu2S
CuFeS2
HgS
CoAsS
CuS
Cu3As
Cu9S5
Cu3AsS4
PbS
Pb4FeSb6S14
FeS2
NiS
MoS2
NiAs
As2S3
NiAs2
FeS2
Fe(1-x)S
AsS
(Co,Ni)As2-3/(Co,Ni)As3x
ZnS
Sb2S3
(Cu, Fe)12Sb4S13
Isometric
Monoclinic
Tetragonal/ Isometric
Orthorhombic
Monoclinic
Tetragonal
Hexagonal
Isometric
Hexagonal
Isometric
Hexagonal (trigonal)
Orthorhombic
Isometric
Monoclinic
Orthorhombic
Hexagonal
Hexagonal
Hexagonal
Monoclinic (combined with realgar)
Orthorhombic
Isometric
Variable
Monoclinic (combined with orpiment)
Isometric
Isometric
Orthorhombic
Isometric
Sulfides, Sulfosalts and Arsenides
As-ore
As-ore
As-ore
Mineral
Formula
System
Argentite
Arsenopyrite
Bornite
Boulangerite
Chalcocite
Chalcopyrite
Cinnabar
Cobaltite
Covellite
Domeykite
Digenite
Enargite
Galena
Jamsonite
Marcasite
Millerite
Molybdenite
Nickeline/Niccolite
Orpiment
Pararamnelsbergite
Pyrite
Pyrrhotite
Realgar
Skutterudite/smaltite
Sphalerite
Stibnite
Tetrahedrite
Ag2S
FeAsS
Cu5FeS4
Pb5Sb4S11
Cu2S
CuFeS2
HgS
CoAsS
CuS
Cu3As
Cu9S5
Cu3AsS4
PbS
Pb4FeSb6S14
FeS2
NiS
MoS2
NiAs
As2S3
NiAs2
FeS2
Fe(1-x)S
AsS
(Co,Ni)As2-3/(Co,Ni)As3x
ZnS
Sb2S3
(Cu, Fe)12Sb4S13
Isometric
Monoclinic
Tetragonal/ Isometric
Orthorhombic
Monoclinic
Tetragonal
Hexagonal
Isometric
Hexagonal
Isometric
Hexagonal (trigonal)
Orthorhombic
Isometric
Monoclinic
Orthorhombic
Hexagonal
Hexagonal
Hexagonal
Monoclinic (combined with realgar)
Orthorhombic
Isometric
Variable
Monoclinic (combined with orpiment)
Isometric
Isometric
Orthorhombic
Isometric
Sulfides, Sulfosalts and Arsenides
Ni-ore
Ni-ore
Ni-ore
Ni-ore
Mineral
Formula
System
Argentite
Arsenopyrite
Bornite
Boulangerite
Chalcocite
Chalcopyrite
Cinnabar
Cobaltite
Covellite
Domeykite
Digenite
Enargite
Galena
Jamsonite
Marcasite
Millerite
Molybdenite
Nickeline/Niccolite
Orpiment
Pararamnelsbergite
Pyrite
Pyrrhotite
Realgar
Skutterudite/smaltite
Sphalerite
Stibnite
Tetrahedrite
Ag2S
FeAsS
Cu5FeS4
Pb5Sb4S11
Cu2S
CuFeS2
HgS
CoAsS
CuS
Cu3As
Cu9S5
Cu3AsS4
PbS
Pb4FeSb6S14
FeS2
NiS
MoS2
NiAs
As2S3
NiAs2
FeS2
Fe(1-x)S
AsS
(Co,Ni)As2-3/(Co,Ni)As3x
ZnS
Sb2S3
(Cu, Fe)12Sb4S13
Isometric
Monoclinic
Tetragonal/ Isometric
Orthorhombic
Monoclinic
Tetragonal
Hexagonal
Isometric
Hexagonal
Isometric
Hexagonal (trigonal)
Orthorhombic
Isometric
Monoclinic
Orthorhombic
Hexagonal
Hexagonal
Hexagonal
Monoclinic (combined with realgar)
Orthorhombic
Isometric
Variable
Monoclinic (combined with orpiment)
Isometric
Isometric
Orthorhombic
Isometric
Sulfides, Sulfosalts and Arsenides
Cu-ore
Cu-ore
Cu-ore
Mineral
Formula
System
Argentite
Arsenopyrite
Bornite
Boulangerite
Chalcocite
Chalcopyrite
Cinnabar
Cobaltite
Covellite
Domeykite
Digenite
Enargite
Galena
Jamsonite
Marcasite
Millerite
Molybdenite
Nickeline/Niccolite
Orpiment
Pararamnelsbergite
Pyrite
Pyrrhotite
Realgar
Skutterudite/smaltite
Sphalerite
Stibnite
Tetrahedrite
Ag2S
FeAsS
Cu5FeS4
Pb5Sb4S11
Cu2S
CuFeS2
HgS
CoAsS
CuS
Cu3As
Cu9S5
Cu3AsS4
PbS
Pb4FeSb6S14
FeS2
NiS
MoS2
NiAs
As2S3
NiAs2
FeS2
Fe(1-x)S
AsS
(Co,Ni)As2-3/(Co,Ni)As3x
ZnS
Sb2S3
(Cu, Fe)12Sb4S13
Isometric
Monoclinic
Tetragonal/ Isometric
Orthorhombic
Monoclinic
Tetragonal
Hexagonal
Isometric
Hexagonal
Isometric
Hexagonal (trigonal)
Orthorhombic
Isometric
Monoclinic
Orthorhombic
Hexagonal
Hexagonal
Hexagonal
Monoclinic (combined with realgar)
Orthorhombic
Isometric
Variable
Monoclinic (combined with orpiment)
Isometric
Isometric
Orthorhombic
Isometric
Sulfides etc.
Sulfides come in two distinct structural coordinations (and a
third that is a more “complex” mixture of the two).
Sulfides etc.
1) Tetrahedral: S (and As) are closely packed and all metal ions
are in tetrahedral coordination. Solid solutions are possible.
Sphalerite
Chalcopyrite
Bornite
Enargite
Sulfides etc.
2) Octahedral: S (and As) are closely packed and all metal ions
are in octahedral coordination.
Galena
Pyrrhotite
Niccolite
Sulfides etc.
3) Complex coordinations: either tetragonal or octahedral
Pentlandite
Molybdenite
Millerite
Cinnabar
Covellite
Argentite
Pyrite
Marcasite
Cobaltite
Arsenopyrite
Skutterudite
Stibnite
Tetrahedrite
Orpiment
Realgar
Sulfides etc.
Cu-Fe sulfides
assemblages plot
Source: Perkins, D., 2002.
Mineralogy. Second Ed., Prentice
Hall, New Jersey, 483p.
Sulfides etc.
Cu-Fe sulfides
assemblages plot
Tie lines connect minerals
that normally co-exist
under specific conditions
of P and T
Sulfides etc.
Cu-Fe sulfides
assemblages plot
Mineral assemblages found in ore
deposits
Covellite/digenite/bornite assemblage
Sulfides etc.
Today’s dog and pony mineral show features Copper Sulfides:
Covellite
Bornite
Chalcocite
CuS
Cu5FeS4
Cu2S
Hexagonal
Isometric
Monoclinic
Other sulfides worth mentioning (and showing):
Argentite
Pyrrhotite
Realgar
Orpiment
Stibnite
Arsenopyrite
Ag2S
Fe(1-x)S
AsS
As2S3
Sb2S3
FeAsS
Isometric
Variable
Monoclinic
Monoclinic
Orthorhombic
Triclinic
Sulfide Minerals
Covellite (CuS)
Crystal: Hexagonal
Pt. Group: 6/m 2/m 2/m
Habit: platy
SG: 4.6
H: 1.5-2
L: metallic to submetallic
Col: indigo blue
Str: dark grey
Clev: perfect (001)
Name derivation: After N. I. Covelli (1790-1829), who found the mineral on Mt. Vesuvius
Sulfide Minerals
Covellite (CuS)
Occurrence: near surface
hydrothermal deposits, porphyry
igneous rocks (porphyry copper
deposits).
Associated Mins: bornite,
chalcopyrite and pyrite
Related Mins: forms solid solutions
with klockmannite [CuSe]
May be confused with: nothing
Sulfide Minerals
Bornite (Cu5FeS4)
Crystal: Orthorhombic
Pt. Group: 2/m2/m2/m
Habit: tabular, commonly striated
SG: 6
H: 3
L: metallic
Col: bronze to iron black
Str: dark grey to black
Clev: poor {111}
Name derivation: After I. von Born (1742-1791), a German mineralogist
Sulfide Minerals
Bornite (Cu5FeS4)
Occurrence: sulfide veins, secondary
(enriched) sulfide deposits.
Associated Mins: chalcopyrite,
chalcocite, covellite, pyrrhotite,
quartz and pyrite
Related Mins: chalcopyrite [CuFe S2]
May be confused with: niccolite,
pyrrhotite, chalcocite and chalcopyrite
Sulfide Minerals
Chalcocite (Cu2S)
Crystal: Monoclinic
Pt. Group: 2/m
Habit: massive
SG: 5.8
H: 2.5-3
L: metallic
Col: blue-white to lead grey
Str: grey-black
Clev: poor {110}
Name derivation: from the Greek chalkos meaning “copper”
Sulfide Minerals
Chalcocite (Cu2S)
Occurrence: common primary and
secondary mineral in sulfide veins
and alteration zones.
Associated Mins: bornite, enargite,
galena, tetrahedrite, cuprite,
chalcopyrite and pyrite
Related Mins: digenite is a similar
species [Cu2-xS]
May be confused with: argentite and
bornite
Copper
Copper
Copper Emplacement
Copper ores are widely
disseminated throughout
the world.
One of the more classic
deposits was mined for
decades near Butte
Montana.
•Porphyry copper deposit
•Hydrothermal veins
cross-cutting granites
Porphyry Copper Ores
Plate Tectonic Setting
John, D.A., (ed) 2010, Porphyry Copper Deposit Model, USGS
Special Investigations Report 2010-5070-B;
http://pubs.usgs.gov
Porphyry Copper Ores
1) Primary mineralization (hypothermal fluids ~400°C)
http://reynolds.asu.edu/sierra_cobre/p_formation.htm
Porphyry Copper Ores
2) Supergene mineralization (epithermal fluids ~25°C)
Porphyry Copper Ores
3) Burial
Sulfide Chemistry
Copper sulfide precipitation is controlled by
1) temperature (high to medium)
2) pH (acidity promotes Cu+ solution)
3) Sulfur content (as S2- or SO2)
4Cu+ + 4Fe2+ 8H2S +O2 →4CuFeS2 + 12 H+ +2H2O
Sulfide Chemistry
Other considerations:
1) Production of sericite [KAl2(Si3Al)O10(OH,F)2] is accelerated in acidic
solutions and this lowers temperature of CuFeS2 formation
Sulfide Chemistry
Other considerations:
1) Production of sericite [KAl2(Si3Al)O10(OH,F)2] is accelerated in acidic
solutions and this lowers temperature of CuFeS2 formation
2) Hornblende alters to biotite releasing more Fe2+ and promoting
precipitation of CuFeS2
Sulfide Chemistry
Other considerations:
1) Production of sericite [KAl2(Si3Al)O10(OH,F)2] is accelerated in acidic
solutions and this lowers temperature of CuFeS2 formation
2) Hornblende alters to biotite releasing more Fe2+ and promoting
precipitation of CuFeS2
3) at high temperatures, SO2 content is higher than H2S content, but this
changes as the temperature decreases to 400 °C:
4SO2 +4H2O →3H2SO4 + H2S
By the way.....
Gold can also be precipitated in porphyry copper
assemblages: Gold transported as: AuSxx+
AuSxx+ + xH+ →Au0 + XH2S
AuSxx+ + 4Cu+ + 4Fe2+ + (x-1)H2S +O2 →
Au0 + 4CuFeS2 + (12-x) H+ +2H2O
Porphyry Copper Deposits
Today’s dog and pony mineral show features:
Covellite
Bornite
Chalcocite
CuS
Cu5FeS4
Cu2S
Hexagonal
Isometric
Monoclinic
Other sulfides worth mentioning (and showing):
Argentite
Pyrrhotite
Realgar
Orpiment
Stibnite
Arsenopyrite
Ag2S
Fe(1-x)S
AsS
As2S3
Sb2S3
FeAsS
Isometric
Variable
Monoclinic
Monoclinic
Orthorhombic
Triclinic
John, D.A., (ed) 2010, Porphyry Copper Deposit Model, USGS Special Investigations Report 2010-5070-B; http://pubs.usgs.gov
John, D.A., (ed) 2010, Porphyry Copper Deposit Model, USGS Special Investigations Report 2010-5070-B;
http://pubs.usgs.gov
Today’s Stuff To Do
1.
Study your minerals
On Line Lecture
The Sulfides part 2 (lecture 10)
1.
Today’s Lab
First look at minerals in lab!
Prep for our first mineral quiz next Tuesday
1.
2.
GY 302: Crystallography and
Mineralogy
Lecture 9: Sulfides Part 1
Instructor: Dr. Doug Haywick
dhaywick@southalabama.edu
This is a free open access lecture, but not for commercial purposes.
For personal use only.