Modderite
A valid IMA mineral species - grandfathered
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About Modderite
Formula:
CoAs
Colour:
steel grey
Lustre:
Metallic
Hardness:
4
Specific Gravity:
8.28 (Calculated)
Crystal System:
Orthorhombic
Name:
Probably for the type locality
Co-Type Localities:
Dimorph of:
This page provides mineralogical data about Modderite.
Unique Identifiers
Mindat ID:
2738
Long-form identifier:
mindat:1:1:2738:6
IMA Classification of Modderite
Approved, 'Grandfathered' (first described prior to 1959)
First published:
1923
Classification of Modderite
2.CC.15
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
C : Metal Sulfides, M: S = 1: 1 (and similar)
C : With Ni, Fe, Co, PGE, etc.
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
C : Metal Sulfides, M: S = 1: 1 (and similar)
C : With Ni, Fe, Co, PGE, etc.
3.10.9
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.
| Symbol | Source | Reference |
|---|---|---|
| Mod | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Modderite
Metallic
Transparency:
Opaque
Colour:
Steel grey
Streak:
Grey
Hardness:
4 on Mohs scale
Hardness:
VHN100=26 - Vickers
Density:
8.28 g/cm3 (Calculated)
Optical Data of Modderite
Reflectivity:
| Wavelength | R1 (%) |
|---|---|
| 440nm | 37.1% |
| 460nm | 38.0% |
| 480nm | 38.3% |
| 500nm | 39.1% |
| 520nm | 39.2% |
| 540nm | 39.8% |
| 560nm | 39.7% |
| 580nm | 39.6% |
| 600nm | 39.2% |
| 620nm | 39.0% |
| 640nm | 38.2% |
| 660nm | 37.4% |
| 680nm | 37.1% |
| 700nm | 35.5% |
| 720nm | 34.5% |
| 740nm | 34.3% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 39.8%.
Chemistry of Modderite
Mindat Formula:
CoAs
Elements listed:
Common Impurities:
Ni
Crystallography of Modderite
Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Cell Parameters:
a = 3.458 Å, b = 5.869 Å, c = 5.292 Å
Ratio:
a:b:c = 0.589 : 1 : 0.902
Unit Cell V:
107.40 ų (Calculated from Unit Cell)
Z:
8
Morphology:
tiny grains, massive
Comment:
Pmcn
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) |
|---|---|---|---|---|---|---|---|
| 0009791 | Modderite | Lyman P S, Prewitt C T (1984) Room- and high-pressure crystal chemistry of CoAs and FeAs Acta Crystallographica B40 14-20 |  | 1984 | synthetic | 0.0001 | 293 |
| 0009792 | Modderite | Lyman P S, Prewitt C T (1984) Room- and high-pressure crystal chemistry of CoAs and FeAs Acta Crystallographica B40 14-20 | | 1984 | synthetic | 0.0001 | 293 |
| 0009793 | Modderite | Lyman P S, Prewitt C T (1984) Room- and high-pressure crystal chemistry of CoAs and FeAs Acta Crystallographica B40 14-20 | | 1984 | synthetic | 2.8 | 293 |
| 0009794 | Modderite | Lyman P S, Prewitt C T (1984) Room- and high-pressure crystal chemistry of CoAs and FeAs Acta Crystallographica B40 14-20 | | 1984 | synthetic | 3.7 | 293 |
| 0009795 | Modderite | Lyman P S, Prewitt C T (1984) Room- and high-pressure crystal chemistry of CoAs and FeAs Acta Crystallographica B40 14-20 | | 1984 | synthetic | 4.9 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 1.97 Å | (100) |
| 2.59 Å | (90) |
| 0.957 Å | (70b) |
| 2.55 Å | (60) |
| 1.047 Å | (60) |
| 0.999 Å | (60) |
| 0.927 Å | (60) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 26 : Hadean detrital minerals | |
| High-? alteration and/or metamorphism | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) |
Type Occurrence of Modderite
Co-Type Localities:
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, 161217.
Geological Setting of Type Material:
Heavy mineral concentrates
Associated Minerals at Type Locality:
Synonyms of Modderite
Lederkobold (in part)
Other Language Names for Modderite
Related Minerals - Strunz-mindat Grouping
| 2.CC. | Eliopoulosite | V7S8 |
| 2.CC. | Tilkerodeite | Pd2HgSe3 |
| 2.CC. | UM2007-26-S:CuFeIrNiPtRh | (Ir,Cu,Ni,Pt,Rh,Fe)9S11 |
| 2.CC. | Proxitwelvefoldite | Pd3Ni4Te8 |
| 2.CC. | Ferrotorryweiserite | Rh5Fe10S16 |
| 2.CC. | Tamuraite | Ir5Fe10S16 |
| 2.CC. | Crowningshieldite | (Ni0.9Fe0.1)S |
| 2.CC. | Kuvaevite | Ir5Ni10S16 |
| 2.CC. | Torryweiserite | Rh5Ni10S16 |
| 2.CC.05 | Achávalite | FeSe |
| 2.CC.05 | Langisite | CoAs |
| 2.CC.05 | Sederholmite | NiSe |
| 2.CC.05 | Freboldite | CoSe |
| 2.CC.05 | Nickeline | NiAs |
| 2.CC.05 | Sobolevskite | PdBi |
| 2.CC.05 | Jaipurite | CoS |
| 2.CC.05 | Kotulskite | Pd(Te,Bi)2-x (x ≈ 0.4) |
| 2.CC.05 | Zlatogorite | NiCuSb2 |
| 2.CC.05 | Stumpflite | PtSb |
| 2.CC.05 | Sudburyite | PdSb |
| 2.CC.05 | Breithauptite | NiSb |
| 2.CC.10 | Pyrrhotite | Fe1-xS |
| 2.CC.10 | Smythite | (Fe,Ni)3+xS4 (x=0-0.3) |
| 2.CC.10 | Troilite | FeS |
| 2.CC.15 | Ruthenarsenite | (Ru,Ni)As |
| 2.CC.15 | Westerveldite | (Fe,Ni,Co)As |
| 2.CC.15 | Minakawaite | RhSb |
| 2.CC.15 | Cherepanovite | RhAs |
| 2.CC.20 | UM1990-38-S:CuFeIrNiPtRh | (Ni,Fe,Rh,Cu,Ir,Pt)S |
| 2.CC.20 | Millerite | NiS |
| 2.CC.20 | Mäkinenite | NiSe |
| 2.CC.25 | Mackinawite | FeS |
| 2.CC.30 | Vavřínite | Ni2SbTe2 |
| 2.CC.30 | Hexatestibiopanickelite | (Pd,Ni)(Sb,Te) ? |
| 2.CC.35b | Cooperite | PtS |
| 2.CC.35a | Vysotskite | PdS |
| 2.CC.35a | Braggite | PdPt3S4 |
| 2.CC.45 | Jacutingaite | Pt2HgSe3 |
| 2.CC.50 | Imgreite | NiTe (?) |
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 Modderite
mindat.org URL:
https://www.mindat.org/min-2738.html
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References for Modderite
Reference List:
Heyding, R. D.; Calvert, L. D. (1957) Arsenides of the transition metals: the arsenides of iron and cobalt. Canadian Journal of Chemistry, 35 (5). 449-457 doi:10.1139/v57-065
Selte, Kari, Kjekshus, Arne, Lindberg, Bengt, Svensson, Sigfrid, Koskikallio, J., Kachi, Sukeji (1971) Structural and Magnetic Properties of CoAs. Acta Chemica Scandinavica, 25. 3277-3284 doi:10.3891/acta.chem.scand.25-3277
Fleischer, Michael, Cabri, Louis J. (1978) New mineral names. American Mineralogist, 63 (5-6) 598-600
Localities for Modderite
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.
Azerbaijan | |
| Makhmudov et al. (1977) |
Canada | |
| Burgess et al. (2014) |
China | |
| Xu Yong and Zhu Xinyou (2000) |
Egypt | |
| Helmy et al. (2021) |
Romania | |
| Hirtopanu et al. (2015) +1 other reference |
Russia | |
| Sidorov et al. (2018) |
South Africa (TL) | |
| Cairncross et al. (1995) |
| Chem.Metall.Min.Soc.S.Africa (1924) |
UK | |
| Nancarrow (1985) +1 other reference |
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Modderfontein 'B' gold mine, Springs, City of Ekurhuleni Metropolitan Municipality, Gauteng, South Africa