Keutschite
A valid IMA mineral species
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About Keutschite
Formula:
Cu2AgAsS4
Lustre:
Metallic
Crystal System:
Tetragonal
Member of:
Name:
Named for Dr. Frank Keutsch (b. 1971), professor of chemistry at Harvard University and specialist in sulphides and sulphosalts.
Type Locality:
Unique Identifiers
Mindat ID:
46159
Long-form identifier:
mindat:1:1:46159:9
GUID
(UUID V4):
(UUID V4):
9aab3718-5989-461a-b07c-2acac0737cbb
IMA Classification of Keutschite
Approved
Approval year:
2014
Classification of Keutschite
2.KA.10
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
K : Sulfarsenates, Sulfantimonates
A : Sulfarsenates with (As,Sb)S4 tetrahedra
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
K : Sulfarsenates, Sulfantimonates
A : Sulfarsenates with (As,Sb)S4 tetrahedra
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 |
---|---|---|
Keu | 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 Keutschite
Metallic
Transparency:
Opaque
Chemistry of Keutschite
Mindat Formula:
Cu2AgAsS4
Elements listed:
Crystallography of Keutschite
Crystal System:
Tetragonal
Class (H-M):
4 2m - Scalenohedral
Space Group:
I4 2m
Setting:
I4 2m
Cell Parameters:
a = 5.5834(15) Å, c = 10.021(3) Å
Ratio:
a:c = 1 : 1.795
Unit Cell V:
312.40 ų (Calculated from Unit Cell)
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
2.79 Å | (ms) |
1.966 Å | (s) |
1.864 Å | (s) |
1.659 Å | (s) |
1.548 Å | (m) |
1.270 Å | (m) |
1.214 Å | (m) |
Comments:
From Type Description.
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
Stage 3b: Earth’s earliest hydrosphere | >4.45 |
12 : Hadean hydrothermal subsurface sulfide deposits (see also #33) |
Type Occurrence of Keutschite
Place of Conservation of Type Material:
Type material is deposited in the reference collection of the Naturhistorisches Museum Wien, Wien, Austria, specimen number N9734
Synonyms of Keutschite
Relationship of Keutschite to other Species
Member of:
Other Members of this group:
Briartite | Cu2(Fe,Zn)GeS4 | Tet. |
Černýite | Cu2(Cd,Zn,Fe)SnS4 | Tet. 4 2m : I4 2m |
Famatinite | Cu3SbS4 | Tet. 4 2m : I4 2m |
Ferrokësterite | Cu2FeSnS4 | Tet. 4 : I4 |
Hocartite | Ag2(Fe2+,Zn)SnS4 | Tet. 4 2m : I4 2m |
Kësterite | Cu2ZnSnS4 | Tet. 4 : I4 |
Kuramite | Cu3SnS4 | Tet. 4 2m : I4 2m |
Luzonite | Cu3AsS4 | Tet. 4 2m : I4 2m |
Omariniite | Cu8Fe2ZnGe2S12 | Orth. 2 2 2 : I2 2 2 |
Permingeatite | Cu3SbSe4 | Tet. 4 2m : I4 2m |
Petrukite | (Cu,Fe,Zn,Ag)3(Sn,In)S4 | Orth. mm2 : Pmn21 |
Pirquitasite | Ag2ZnSnS4 | Tet. 4 : I4 |
Richardsite | Zn2CuGaS4 | Tet. 4 2m : I4 2m |
Stannite | Cu2FeSnS4 | Tet. 4 2m : I4 2m |
Stannoidite | Cu+6Cu2+2(Fe2+,Zn)3Sn2S12 | Orth. 2 2 2 : I2 2 2 |
UM1984-30-S:CuFeSn | Cu2Fe2Sn3S7 | |
Unnamed (Cu-Zn-In Sulphide) | CuZn2InS4 | |
Velikite | Cu2HgSnS4 | Tet. 4 : I4 |
Zincobriartite | Cu2(Zn,Fe)(Ge,Ga)S4 | Tet. 4 2m : I4 2m |
Common Associates
Associated Minerals Based on Photo Data:
2 photos of Keutschite associated with Manganoquadratite | AgMnAsS3 |
2 photos of Keutschite associated with Calcite | CaCO3 |
2 photos of Keutschite associated with Alabandite | MnS |
2 photos of Keutschite associated with Proustite | Ag3AsS3 |
1 photo of Keutschite associated with Bournonite-Seligmannite Series | |
1 photo of Keutschite associated with Tennantite-Tetrahedrite Series | |
1 photo of Keutschite associated with Luzonite | Cu3AsS4 |
1 photo of Keutschite associated with Tetrahedrite Subgroup | Cu6(Cu4C2+2)Sb4S12S |
1 photo of Keutschite associated with Chalcopyrite | CuFeS2 |
1 photo of Keutschite associated with Quartz | SiO2 |
Related Minerals - Strunz-mindat Grouping
2.KA.05 | Enargite | Cu3AsS4 |
2.KA.05 | Petrukite | (Cu,Fe,Zn,Ag)3(Sn,In)S4 |
2.KA.10 | Briartite | Cu2(Fe,Zn)GeS4 |
2.KA.10 | Famatinite | Cu3SbS4 |
2.KA.10 | Luzonite | Cu3AsS4 |
2.KA.10 | Permingeatite | Cu3SbSe4 |
2.KA.10 | Barquillite | Cu2CdGeS4 |
2.KA.10 | Zincobriartite | Cu2(Zn,Fe)(Ge,Ga)S4 |
2.KA.15 | Fangite | Tl3AsS4 |
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 Keutschite
mindat.org URL:
https://www.mindat.org/min-46159.html
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References for Keutschite
Reference List:
Localities for Keutschite
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).
Struck out - Mineral was erroneously reported from this locality.
Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.
All localities listed without proper references should be considered as questionable.
Germany | |
| Kolitsch et al. (2019) |
Peru (TL) | |
| Mineralogical Magazine +1 other reference |
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Uchucchacua Mine, Oyón District, Oyón Province, Lima, Peru