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Arsenopyrite

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Formula:
FeAsS
Colour:
Silver-white to steel-gray, may have a slight yellow appearance
Lustre:
Metallic, Sub-Metallic
Hardness:
5½ - 6
Specific Gravity:
6.07
Crystal System:
Monoclinic
Name:
Named in 1847 by Ernst Friedrich Glocker for its composition, a contraction of the antiquated term "arsenical pyrite." Arsenopyrite was known much before 1847 and arsenopyrite, as a name, may be taken as a simple translation of "arsenkies".
Arsenopyrite Group.

For possible Ni-analogue see Unnamed (Ni,Fe,Co)AsS; see also Unnamed (Ni Arsenide Sulphide). Arsenopyrite is closely related to alloclasite, but is not an exact analogue, because of different As-S and S-As ordering.

Arsenopyrite may contain up to about 9 wt.% Co; with higher Co contents, glaucodot will appear as a separate phase (Gammon, 1966).

May be confused with the iron arsenide löllingite.



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Classification of ArsenopyriteHide

Approved, 'Grandfathered' (first described prior to 1959)
2.EB.20

2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
E : Metal Sulfides, M: S <= 1:2
B : M:S = 1:2, with Fe, Co, Ni, PGE, etc.
Dana 7th ed.:
2.12.4.1
2.12.4.1

2 : SULFIDES
12 : AmBnXp, with (m+n):p = 1:2
3.9.12

3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
9 : Sulphides etc. of Fe

Physical Properties of ArsenopyriteHide

Metallic, Sub-Metallic
Transparency:
Opaque
Colour:
Silver-white to steel-gray, may have a slight yellow appearance
Comment:
Tarnished material common
Streak:
Gray-black
Hardness:
5½ - 6 on Mohs scale
Hardness:
VHN100=1081 kg/mm2 - Vickers
Comment:
VHN on (001) section
Tenacity:
Brittle
Cleavage:
Distinct/Good
Distinct on {001}; {010} in traces
Fracture:
Irregular/Uneven
Density:
6.07(15) g/cm3 (Measured)    6.18 g/cm3 (Calculated)

Optical Data of ArsenopyriteHide

Type:
Anisotropic
Anisotropism:
Strong red-violet
Reflectivity:
400nmR1=50.3%R2= 51.8%
420nmR1=50.3%R2= 51.8%
440nmR1=51.3%R2= 51.8%
460nmR1=50.6%R2= 51.8%
480nmR1=51.0%R2= 51.9%
500nmR1=51.4%R2= 51.9%
520nmR1=51.8%R2= 51.9%
540nmR1=52.2%R2= 51.9%
560nmR1=52.5%R2= 51.9%
580nmR1=53.0%R2= 51.8%
600nmR1=53.4%R2= 51.6%
620nmR1=53.6%R2= 51.5%
640nmR1=53.6%R2= 51.3%
660nmR1=53.6%R2= 51.3%
680nmR1=53.4%R2= 51.2%
700nmR1=53.2%R2= 51.0%

Reflectance graph
Graph shows reflectance levels at different wavelengths (in nm). Top of box is 100%. Peak reflectance is 53.6%.
R1 shown in black, R2 shown in red
Colour in reflected light:
White with faint yellow tint
Pleochroism:
Weak
Comments:
White or bluish tint, faint reddish yellow

Chemical Properties of ArsenopyriteHide

Formula:
FeAsS
Common Impurities:
Ag,Au,Co,Sn,Ni,Sb,Bi,Cu,Pb

Crystallography of ArsenopyriteHide

Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/c
Cell Parameters:
a = 5.744 Å, b = 5.675 Å, c = 5.785 Å
β = 112.3°
Ratio:
a:b:c = 1.012 : 1 : 1.019
Unit Cell V:
174.47 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Flat tabular to blocky (sometimes pseudo-octahedral) to prismatic.
Twinning:
Common on {100} and {001}. Contact or penetration on {101}, on {012} trillings or cruciform.
Comment:
Pseudo-orthorhombic, face-centred cell: ~5.7, ~6.4, ~9.6 A.

Crystallographic forms of ArsenopyriteHide

Crystal Atlas:
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Arsenopyrite no.5 - Goldschmidt (1913-1926)
Arsenopyrite no.12 - Goldschmidt (1913-1926)
Arsenopyrite no.14 - Goldschmidt (1913-1926)
Arsenopyrite no.62 - Goldschmidt (1913-1926)
Arsenopyrite no.64 - Goldschmidt (1913-1926)
Arsenopyrite no.113 - Goldschmidt (1913-1926)
3d models and HTML5 code kindly provided by www.smorf.nl.

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Transparency
Opaque | Translucent | Transparent

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X-Ray Powder DiffractionHide

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Radiation - Copper Kα
Data Set:
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
d-spacingIntensity
3.658 (40)
2.866 (5)
2.838 (30)
2.796 (10)
2.677 (100)
2.662 (100)
2.557 (10)
2.440 (90)
2.418 (95)
2.412 (95)
2.204 (25)
2.095 (20)
2.017 (5)
1.961 (50)
1.943 (25)
1.824 (70)
1.814 (90)
1.787 (5)
1.759 (20)
1.750 (5)
1.703 (5)
1.631 (30)
1.608 (25)
1.594 (15)
1.589 (20)
1.543 (20)
1.537 (20)
1.390 (5)
1.343 (15)
Comments:
ICDD 14-218 (Freiberg, Germany)

Synonyms of ArsenopyriteHide

Other Language Names for ArsenopyriteHide

Varieties of ArsenopyriteHide

Cobaltoan ArsenopyriteSynonymous with danaite.

Originally described from Franconia, Grafton Co., New Hampshire, USA.
DanaiteA Co-bearing variety of arsenopyrite.
Originally described from Franconia, Grafton Co., New Hampshire, USA.

Relationship of Arsenopyrite to other SpeciesHide

Other Members of this group:
Glaucodot(Co0.50Fe0.50)AsSOrth. mm2 : Pmn21
GudmunditeFeSbSMon. 2/m : P21/b
Osarsite(Os,Ru)AsSMon.
Ruarsite(Ru,Os)AsSMon.

Common AssociatesHide

Associated Minerals Based on Photo Data:
Quartz733 photos of Arsenopyrite associated with Quartz on mindat.org.
Fluorite293 photos of Arsenopyrite associated with Fluorite on mindat.org.
Muscovite275 photos of Arsenopyrite associated with Muscovite on mindat.org.
Calcite252 photos of Arsenopyrite associated with Calcite on mindat.org.
Siderite246 photos of Arsenopyrite associated with Siderite on mindat.org.
Pyrite229 photos of Arsenopyrite associated with Pyrite on mindat.org.
Chalcopyrite186 photos of Arsenopyrite associated with Chalcopyrite on mindat.org.
Fluorapatite148 photos of Arsenopyrite associated with Fluorapatite on mindat.org.
Sphalerite147 photos of Arsenopyrite associated with Sphalerite on mindat.org.
Ferberite125 photos of Arsenopyrite associated with Ferberite on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

2.EB.05aAurostibiteAuSb2Iso. m3 (2/m 3) : Pa3
2.EB.05bBambollaiteCu(Se,Te)2Tet.
2.EB.05aCattieriteCoS2Iso. m3 (2/m 3) : Pa3
2.EB.05aErlichmaniteOsS2Iso. m3 (2/m 3) : Pa3
2.EB.05aFukuchiliteCu3FeS8Iso. m3 (2/m 3) : Pa3
2.EB.05aGeversitePtSb2Iso. m3 (2/m 3) : Pa3
2.EB.05aHaueriteMnS2Iso. m3 (2/m 3) : Pa3
2.EB.05aInsizwaitePt(Bi,Sb)2
2.EB.05aKrut'aiteCuSe2Iso. m3 (2/m 3) : Pa3
2.EB.05aLauriteRuS2Iso. m3 (2/m 3) : Pa3
2.EB.05aPenroseite(Ni,Co,Cu)Se2Iso. m3 (2/m 3) : Pa3
2.EB.05aPyriteFeS2Iso. m3 (2/m 3) : Pa3
2.EB.05aSperrylitePtAs2Iso. m3 (2/m 3) : Pa3
2.EB.05aTrogtaliteCoSe2
2.EB.05aVaesiteNiS2Iso. m3 (2/m 3) : Pa3
2.EB.05aVillamaninite(Cu,Ni,Co,Fe)S2
2.EB.05aDzharkeniteFeSe2Iso.
2.EB.05aGaotaiiteIr3Te8Iso.
2.EB.10bAlloclasiteCo1-xFexAsSMon. 2 : P21
2.EB.10dCostibiteCoSbSOrth. mm2 : Pmn21
2.EB.10aFerroseliteFeSe2Orth. mmm (2/m 2/m 2/m) : Pnnm
2.EB.10aFrohbergiteFeTe2Orth. mmm (2/m 2/m 2/m) : Pnnm
2.EB.10cGlaucodot(Co0.50Fe0.50)AsSOrth. mm2 : Pmn21
2.EB.10aKulleruditeNiSe2Orth. mmm (2/m 2/m 2/m) : Pnnm
2.EB.10aMarcasiteFeS2Orth. mmm (2/m 2/m 2/m) : Pnnm
2.EB.10aMattagamiteCoTe2Orth.
2.EB.10eParacostibiteCoSbSOrth.
2.EB.10ePararammelsbergiteNiAs2Orth.
2.EB.10fOeniteCoSbAsOrth.
2.EB.15aAnduoite(Ru,Os)As2Orth.
2.EB.15aClinosaffloriteCoAs2Mon. 2/m : P21/m
2.EB.15aLöllingiteFeAs2Orth. mmm (2/m 2/m 2/m) : Pnnm
2.EB.15aNisbiteNiSb2Orth.
2.EB.15aOmeiite(Os,Ru)As2Orth.
2.EB.15cPaxiteCuAs2Mon.
2.EB.15aRammelsbergiteNiAs2Orth. mmm (2/m 2/m 2/m) : Pnnm
2.EB.15aSafflorite(Co,Ni,Fe)As2Orth. mmm (2/m 2/m 2/m) : Pnnm
2.EB.15bSeinäjokite(Fe,Ni)(Sb,As)2Orth.
2.EB.20GudmunditeFeSbSMon. 2/m : P21/b
2.EB.20Osarsite(Os,Ru)AsSMon.
2.EB.20Ruarsite(Ru,Os)AsSMon.
2.EB.25CobaltiteCoAsSOrth. mm2 : Pca21
2.EB.25GersdorffiteNiAsSIso. m3 (2/m 3) : Pa3
2.EB.25Hollingworthite(Rh,Pt,Pd)AsSIso. m3 (2/m 3)
2.EB.25Irarsite(Ir,Ru,Rh,Pt)AsSIso.
2.EB.25JolliffeiteNiAsSeIso. m3 (2/m 3) : Pa3
2.EB.25KrutoviteNiAs2Iso.
2.EB.25MaslovitePtBiTe
2.EB.25MicheneritePdBiTe
2.EB.25PadmaitePdBiSeIso.
2.EB.25PlatarsitePtAsSIso.
2.EB.25TestibiopalladitePdTe(Sb,Te)Iso.
2.EB.25TolovkiteIrSbSIso.
2.EB.25UllmanniteNiSbSIso. 2 3 : P21 3
2.EB.25Willyamite(Co,Ni)SbS
2.EB.25ChangchengiteIrBiSIso.
2.EB.25MayingiteIrBiTeIso.
2.EB.25Hollingsworthite(Rh,Pt,Pd)AsS
2.EB.25KalungaitePdAsSeIso. m3 (2/m 3) : Pa3
2.EB.25MilotaitePdSbSeIso. 2 3 : P21 3
2.EB.30UrvantsevitePd(Bi,Pb)2Tet.
2.EB.35RheniiteReS2Tric.

Related Minerals - Dana Grouping (8th Ed.)Hide

2.12.4.2GudmunditeFeSbSMon. 2/m : P21/b
2.12.4.3Osarsite(Os,Ru)AsSMon.
2.12.4.4Ruarsite(Ru,Os)AsSMon.
2.12.4.5Iridarsenite(Ir,Ru)As2Mon.
2.12.4.6ClinosaffloriteCoAs2Mon. 2/m : P21/m

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

3.9.1PyrrhotiteFe7S8Mon.
3.9.3PyriteFeS2Iso. m3 (2/m 3) : Pa3
3.9.4MarcasiteFeS2Orth. mmm (2/m 2/m 2/m) : Pnnm
3.9.5GreigiteFe2+Fe3+2S4Iso. m3m (4/m 3 2/m) : Fd3m
3.9.6Mackinawite(Fe,Ni)9S8Tet. 4/mmm (4/m 2/m 2/m) : P4/nmm
3.9.7Smythite(Fe,Ni)3+xS4 (x=0-0.3)Trig. 3m (3 2/m) : R3m
3.9.8Achávalite(Fe,Cu)SeHex. 6/mmm (6/m 2/m 2/m) : P63/mmc
3.9.9FerroseliteFeSe2Orth. mmm (2/m 2/m 2/m) : Pnnm
3.9.10FrohbergiteFeTe2Orth. mmm (2/m 2/m 2/m) : Pnnm
3.9.11LöllingiteFeAs2Orth. mmm (2/m 2/m 2/m) : Pnnm
3.9.13GudmunditeFeSbSMon. 2/m : P21/b

Fluorescence of ArsenopyriteHide

Not fluorescent

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

Arsenopyrite in petrologyHide

An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.

References for ArsenopyriteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Buerger, M.J. (1936) The symmetry and crystal structure of the minerals of the arsenopyrite group. Zeitschrift für Kristallographie: 95: 83-113.
Palache, C., Berman, H., Frondel, C. (1944) The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Volume I: Elements, Sulfides, Sulfosalts, Oxides. John Wiley and Sons, Inc., New York. 7th edition, revised and enlarged: 316-322.
Morimoto, N., Clark, L.A. (1961) Arsenopyrite crystal-chemical relations. American Mineralogist: 46: 1448-1469.
International Mineralogical Association (1962) International Mineralogical Association: Commission on new minerals and mineral names. Mineralogical Magazine: 33: 260-263.
Brostigen, G., Kjekshus, A., Rømming, C. (1973) Compounds with the marcasite type crystal structure. VIII. Redetermination of the prototype. Acta Chemica Scandinavica: 27: 2791-2796.
Kretschmar, U., Scott, S.D. (1976) Phase relations involving arsenopyrite in the system Fe-As-S and their application. The Canadian Mineralogist: 14: 364-386.
Tossell, J.A., Vaughan, D.J., Burdett, J.K. (1981) Pyrite, marcasite, and arsenopyrite type minerals: Crystal chemical and structural principles. Physics and Chemistry of Minerals: 7: 177-184.
Fuess, H., Kratz, T., Topel-Schadt, J., Miehe, G. (1987) Crystal structure refinement and electron microscopy of arsenopyrite. Zeitschrift für Kristallographie: 179: 335-346.
Fleet, M.E., Mumin, A.H. (1997) Gold-bearing arsenian pyrite and marcasite and arsenopyrite from Carlin-trend gold deposits and laboratory synthesis. American Mineralogist: 82: 182-193.
Schaufuss, A.G., Nesbitt, H.W., Scaini, M.J., Hoechst, H., Bancroft, M.G., Szargan, R. (2000) Reactivity of surface sites on fractured arsenopyrite (FeAsS) toward oxygen. American Mineralogist: 85: 1754-1766.
Tomkins A.G., Frost B.R., Pattison D.R.M. (2006) Arsenopyrite melting during metamorphism of sulfide ore deposits. The Canadian Mineralogist: 44: 1045-1062.
Yang, H., Downs, R.T. (2008) Crystal structure of glaucodot, (Co,Fe)AsS, and its relationships to marcasite and arsenopyrite, American Mineralogist: 93: 1183-1186.
Bindi L., Moëlo Y., Léone P., Suchaud M. (2012) Stoichiometric arsenopyrite, FeAsS, from La Roche-Balue Quarry, Loire-Atlantique, France: Crystal structure and Mössbauer study. The Canadian Mineralogist: 50: 471-479.
Kharbish, S., András, P. (2014) Investigations of the Fe sulfosalts berthierite, garavellite, arsenopyrite and gudmundite by Raman spectroscopy. Mineralogical Magazine: 78: 1287-1299.

Internet Links for ArsenopyriteHide

Localities for ArsenopyriteHide

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListShow