Alloclasite
A valid IMA mineral species - grandfathered
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About Alloclasite
Formula:
Co1-xFexAsS
(x ≈ 0-0.35)
Colour:
Steel gray to silver
Lustre:
Metallic
Hardness:
5
Specific Gravity:
5.95
Crystal System:
Monoclinic
Member of:
Name:
For the Greek άλλος ("allos") for "other" and κλάσις ("klasis"), "to break", because its cleavage was believed to be different from marcasite.
Type Locality:
See also the chemically very similar Cobaltite and Glaucodot. Compare 'UM1966-01-As:CoNiS'.
Fe content is distinctly higher than that of cobaltite, and the Fe usually occupies about 25% of the (Co,Fe) site (Kingston, 1971).
Fe content is distinctly higher than that of cobaltite, and the Fe usually occupies about 25% of the (Co,Fe) site (Kingston, 1971).
Unique Identifiers
Mindat ID:
134
Long-form identifier:
mindat:1:1:134:2
GUID
(UUID V4):
(UUID V4):
8b2595eb-635e-4d0d-ad1b-89c8b48dc8f2
IMA Classification of Alloclasite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
CoAsS
First published:
1866
Classification of Alloclasite
2.EB.10b
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.
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.
2.12.6.2
2 : SULFIDES
12 : AmBnXp, with (m+n):p = 1:2
2 : SULFIDES
12 : AmBnXp, with (m+n):p = 1:2
3.10.16
3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
10 : Sulphides etc. of Co
3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
10 : Sulphides etc. of Co
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference |
|---|---|---|
| Acl | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Alo | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Alloclasite
Metallic
Transparency:
Opaque
Colour:
Steel gray to silver
Streak:
Nearly black
Hardness:
5 on Mohs scale
Hardness:
VHN100=818 - 940 kg/mm2 - Vickers
Tenacity:
Brittle
Cleavage:
Perfect
perfect on {101}
distinct on {010}
perfect on {101}
distinct on {010}
Fracture:
Irregular/Uneven, Sub-Conchoidal
Density:
5.95 g/cm3 (Measured) 6.188 g/cm3 (Calculated)
Optical Data of Alloclasite
Reflectivity:
| Wavelength | R1 | R2 |
|---|---|---|
| 400nm | 49.5% | 48.2% |
| 420nm | 48.7% | 48.3% |
| 440nm | 48.2% | 48.6% |
| 460nm | 47.8% | 48.8% |
| 480nm | 47.6% | 49.2% |
| 500nm | 47.6% | 49.7% |
| 520nm | 47.8% | 50.1% |
| 540nm | 48.0% | 50.4% |
| 560nm | 48.1% | 50.5% |
| 580nm | 48.4% | 50.6% |
| 600nm | 48.6% | 50.7% |
| 620nm | 48.8% | 50.7% |
| 640nm | 49.0% | 50.5% |
| 660nm | 49.1% | 50.3% |
| 680nm | 49.1% | 50.1% |
| 700nm | 49.2% | 49.9% |
Graph shows reflectance levels at different wavelengths (in nm). Top of box is 100%. Peak reflectance is 50.7%.
R1 shown in black, R2 shown in red
Chemistry of Alloclasite
Mindat Formula:
Co1-xFexAsS
(x ≈ 0-0.35)
(x ≈ 0-0.35)
Elements listed:
Common Impurities:
Ni
Crystallography of Alloclasite
Crystal System:
Monoclinic
Class (H-M):
2 - Sphenoidal
Space Group:
P21
Cell Parameters:
a = 4.661 Å, b = 5.602 Å, c = 3.411 Å
β = 90.03°
β = 90.03°
Ratio:
a:b:c = 0.832 : 1 : 0.609
Unit Cell V:
89.06 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Crystals are prismatic parallel [010] , to 5 mm, in columnar to radiating aggregates; commonly massive.
Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0005134 | Alloclasite | Scott J D, Nowacki W (1976) The crystal structure of alloclasite, CoAsS, and the alloclasite-cobaltite transformation The Canadian Mineralogist 14 561-566 |  | 1976 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.58 Å | (30) |
| 2.802 Å | (30) |
| 2.750 Å | (100) |
| 2.469 Å | (90) |
| 2.401 Å | (50) |
| 1.817 Å | (70) |
| 1.707 Å | (30) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) | |
| High-𝑇 alteration and/or metamorphism | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) |
Geological Setting:
In calcite or quartz veins of apparently low-temperature, late-stage hydrothermal origin. Also in silicified, recrystallized metamorphic rock.
Type Occurrence of Alloclasite
General Appearance of Type Material:
Steel gray and fissile.
Place of Conservation of Type Material:
n.d.
Reference:
Tschermak, G. (1866) Der alloklas und der sogenannte glaukodot von Orawicza. Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften, 53, 220-225.
Synonyms of Alloclasite
Other Language Names for Alloclasite
Relationship of Alloclasite to other Species
Member of:
Other Members of this group:
| Anduoite | (Ru,Os)As2 | Orth. |
| Clinosafflorite | CoAs2 | Mon. 2/m : P21/m |
| Costibite | CoSbS | Orth. mm2 : Pmn21 |
| Löllingite | FeAs2 | Orth. mmm (2/m 2/m 2/m) : Pnnm |
| Nisbite | NiSb2 | Orth. mmm (2/m 2/m 2/m) : Pnnm |
| Oenite | CoSbAs | Orth. |
| Omeiite | (Os,Ru)As2 | Orth. |
| Paracostibite | CoSbS | Orth. mmm (2/m 2/m 2/m) : Pbca |
| Pararammelsbergite | NiAs2 | Orth. mmm (2/m 2/m 2/m) : Pbca |
| Rammelsbergite | NiAs2 | Orth. mmm (2/m 2/m 2/m) : Pnnm |
| Safflorite | (Co,Ni,Fe)As2 | Orth. mmm (2/m 2/m 2/m) : Pnnm |
| UM1998-01-AsSb:CoFeNi | (Fe,Ni)SbAs |
Common Associates
Associated Minerals Based on Photo Data:
| 4 photos of Alloclasite associated with Quartz | SiO2 |
| 3 photos of Alloclasite associated with Chalcopyrite | CuFeS2 |
| 2 photos of Alloclasite associated with Scorodite | Fe3+AsO4 · 2H2O |
| 2 photos of Alloclasite associated with Chlorite Group | |
| 2 photos of Alloclasite associated with Silver | Ag |
| 2 photos of Alloclasite associated with Safflorite | (Co,Ni,Fe)As2 |
| 2 photos of Alloclasite associated with Erythrite | Co3(AsO4)2 · 8H2O |
| 2 photos of Alloclasite associated with Fukuchilite | Cu3FeS8 |
| 2 photos of Alloclasite associated with Arsenopyrite | FeAsS |
| 1 photo of Alloclasite associated with Spherocobaltite | CoCO3 |
Related Minerals - Strunz-mindat Grouping
| 2.EB. | Iridarsenite | (Ir,Ru)As2 |
| 2.EB. | Selenolaurite | RuSe2 |
| 2.EB. | Andrieslombaardite | RhSbS |
| 2.EB. | Kanatzidisite | (SbBiS3)2Te2 |
| 2.EB.05a | Aurostibite | AuSb2 |
| 2.EB.05b | Bambollaite | Cu(Se,Te)2 |
| 2.EB.05a | Cattierite | CoS2 |
| 2.EB.05a | Erlichmanite | OsS2 |
| 2.EB.05a | Fukuchilite | Cu3FeS8 |
| 2.EB.05a | Geversite | PtSb2 |
| 2.EB.05a | Hauerite | MnS2 |
| 2.EB.05a | Insizwaite | Pt(Bi,Sb)2 |
| 2.EB.05a | Krut'aite | CuSe2 |
| 2.EB.05a | Laurite | RuS2 |
| 2.EB.05a | Penroseite | (Ni,Co,Cu)Se2 |
| 2.EB.05a | Pyrite | FeS2 |
| 2.EB.05a | Sperrylite | PtAs2 |
| 2.EB.05a | Trogtalite | CoSe2 |
| 2.EB.05a | Vaesite | NiS2 |
| 2.EB.05a | Villamanínite | (Cu,Ni,Co,Fe)S2 |
| 2.EB.05a | Dzharkenite | FeSe2 |
| 2.EB.05a | Gaotaiite | Ir3Te8 |
| 2.EB.05a v | Cayeuxite | |
| 2.EB.10d | Costibite | CoSbS |
| 2.EB.10a | Ferroselite | FeSe2 |
| 2.EB.10a | Frohbergite | FeTe2 |
| 2.EB.10c | Glaucodot | (Co0.50Fe0.50)AsS |
| 2.EB.10a | Kullerudite | NiSe2 |
| 2.EB.10a | Marcasite | FeS2 |
| 2.EB.10a | Mattagamite | CoTe2 |
| 2.EB.10e | Paracostibite | CoSbS |
| 2.EB.10e | Pararammelsbergite | NiAs2 |
| 2.EB.10f | Oenite | CoSbAs |
| 2.EB.10a | Petříčekite | CuSe2 |
| 2.EB.15a | Anduoite | (Ru,Os)As2 |
| 2.EB.15a | Clinosafflorite | CoAs2 |
| 2.EB.15a | Löllingite | FeAs2 |
| 2.EB.15a | Nisbite | NiSb2 |
| 2.EB.15a | Omeiite | (Os,Ru)As2 |
| 2.EB.15c | Paxite | CuAs2 |
| 2.EB.15a | Rammelsbergite | NiAs2 |
| 2.EB.15a | Safflorite | (Co,Ni,Fe)As2 |
| 2.EB.15b | Seinäjokite | (Fe,Ni)(Sb,As)2 |
| 2.EB.20 | Arsenopyrite | FeAsS |
| 2.EB.20 | Gudmundite | FeSbS |
| 2.EB.20 | Osarsite | (Os,Ru)AsS |
| 2.EB.20 | Ruarsite | (Ru,Os)AsS |
| 2.EB.25 va | Antimony-bearing Gersdorffite | Ni(As,Sb)S |
| 2.EB.25 | Cobaltite | CoAsS |
| 2.EB.25 | Gersdorffite | NiAsS |
| 2.EB.25 | Hollingworthite | (Rh,Pt,Pd)AsS |
| 2.EB.25 | Irarsite | (Ir,Ru,Rh,Pt)AsS |
| 2.EB.25 | Jolliffeite | NiAsSe |
| 2.EB.25 | Krutovite | NiAs2 |
| 2.EB.25 | Maslovite | PtBiTe |
| 2.EB.25 | Michenerite | PdBiTe |
| 2.EB.25 | Padmaite | PdBiSe |
| 2.EB.25 | Platarsite | Pt(As,S)2 |
| 2.EB.25 | Testibiopalladite | PdSbTe |
| 2.EB.25 | Tolovkite | IrSbS |
| 2.EB.25 | Ullmannite | NiSbS |
| 2.EB.25 | Willyamite | CoSbS |
| 2.EB.25 | Changchengite | IrBiS |
| 2.EB.25 | Mayingite | IrBiTe |
| 2.EB.25 | Kalungaite | PdAsSe |
| 2.EB.25 | Milotaite | PdSbSe |
| 2.EB.25 | Paragersdorffite | Ni(As,S)2 |
| 2.EB.25 | Orthogersdorffite | NiAsS |
| 2.EB.25 | Kvačekite | NiSbSe |
| 2.EB.30 | Urvantsevite | Pd(Bi,Pb)2 |
| 2.EB.35 | Rheniite | ReS2 |
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Alloclasite
mindat.org URL:
https://www.mindat.org/min-134.html
Please feel free to link to this page.
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References for Alloclasite
Reference List:
Maurel, Colette, Picot, Paul (1973) Sur le mécanisme de la transformation de l'alloclasite en cobaltite : cas du gisement du Lautaret. Bulletin de Minéralogie, 96 (4) 292-297 doi:10.3406/bulmi.1973.6831
Localities for Alloclasite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Argentina | |
| Brodtkorb (2002) |
Australia | |
| Croxford (1974) |
| Sielecki (1988) | |
| Jeff Steadman |
| Lawrence et al (1998) |
| Williams et al 2015 +1 other reference | |
| Croxford (1974) |
| Mineralogical Society of America - ... |
Austria | |
| Leitner (2013) |
| Raith et al. (2015) | |
| Raith et al. (2015) |
| Tropper et al. (2011) |
Brazil | |
| Campbell (2012) |
Bulgaria | |
| Kerestedjian T (1984) |
Canada | |
| Montgomery (n.d.) |
| Stefanie M. Brueckner et al. (2016) |
| [www.ontariominerals.com] +2 other references |
| |
| Reiner Mielke |
| Reiner Mielke (2009) | |
| Mineralogical Society of America - ... +1 other reference | |
| Sabina (2000) |
| Mineralogical Society of America - ... |
China | |
| Xiong et al. (2022) |
| Wang et al. (2022) |
| Zhaolong Li et al. (1981) |
| Yuanren Chen (1976) |
Czech Republic | |
| Lapis 2002 (7/8) |
| Ondruš et al. (2003) | |
Finland | |
| Pere Tuomas (2009) |
France | |
| Mineralogical Society of America - ... |
| R. Pierrot | |
Germany | |
| Kolitsch (1996) |
| |
| Lapis (2) |
| Wagner et al. (2002) |
| Joachim Gröbner (2019) |
| Wittern (2001) |
| Mills et al. (2020) | |
| Henrich (2009) |
| Golze +3 other references | |
| Wittern (2001) |
| |
| Rolf Golze +3 other references |
| Golze +3 other references |
| Sandmann et al. (2015) |
Greece | |
| Rieck et al. (2022) |
India | |
| Goldschmidt Conference Abstracts (2011) |
Indonesia | |
| Dana et al. (2022) |
Iran | |
| Rezazadeh et al. (2020) |
Ireland | |
| S. MORETON et al. (1999) |
Italy | |
| Vergani F. et al. (2019) |
| Ciriotti et al. (2010) |
| Sabelli (2000) |
Japan | |
| Kingstone (1971) |
| Ohnishi et al (2004) |
Kazakhstan | |
| Kovalev et al. (2018) |
Mongolia | |
| Khishgee et al. (2015) |
Morocco | |
| S. Weiß: Lapis 31 (7/8) |
| Gunnar Färber and Thomas Witzke (2010) |
| Georges Favreau collection |
| Joachim Esche collection (specimen obtained from Jean-Pierre Barral) |
Norway | |
| Kullerud et al. (2016) |
Papua New Guinea | |
| Noku et al. (2012) |
Portugal | |
| Marques de Sá et al. (2010) |
| Cabri et al. (1998) |
Romania | |
| Szakáll (2002) |
| Tschermak (1866) +2 other references |
Russia | |
| Melekestseva (2005) |
| AA et al. (2021) |
| Bazai et al. (2009) |
| Azovskova et al. (2013, January) |
| Vinogradova +2 other references |
| Gas’kov (2008) |
Spain | |
| Tornos et al. (1998) |
| Bocamina (4) |
| Fanlo et al. (2004) +1 other reference |
UK | |
| Embrey et al. (1987) |
| Betterton (2000) |
| Mineralogical Society of America - ... +2 other references |
| Solferino et al. (2021) |
USA | |
| - (2008) |
| Anthony et al. (1995) |
| Mineralogical Society of America - ... |
| Bart Cannon Collection |
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Bou Azzer mining district, Drâa-Tafilalet Region, Morocco