Keutschite
A valid IMA mineral species
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About Keutschite
Dr. Frank Keutsch
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
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.
Germany | |
| Kolitsch et al. (2019) |
Peru (TL) | |
| Mineralogical Magazine +1 other reference |
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Uchucchacua Mine, Oyón District, Oyón Province, Lima, Peru