Grundmannite
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About Grundmannite
Günter Grundmann
Formula:
CuBiSe2
Colour:
Black
Lustre:
Metallic
Hardness:
2 - 2½
Specific Gravity:
6.582 (Calculated)
Crystal System:
Orthorhombic
Member of:
Name:
Named after Günter Grundmann, in recognition of his pioneering work on the El Dragón mine.
Type Locality:
Dimorph of:
Isostructural with:
The Se analogue of emplectite.
The two independent selenium positions are in well accordance to two sulfur sites of the isotypic emplectite. Bismuth forms BiSe3 trigonal pyramids, while Cu is present as nearly regular CuSe4 tetrahedra.
The two independent selenium positions are in well accordance to two sulfur sites of the isotypic emplectite. Bismuth forms BiSe3 trigonal pyramids, while Cu is present as nearly regular CuSe4 tetrahedra.
Classification of Grundmannite
Approved
Approval Year:
2015
Physical Properties of Grundmannite
Metallic
Transparency:
Opaque
Colour:
Black
Streak:
Black
Hardness:
2 - 2½ on Mohs scale
Hardness:
VHN20=45 - 61 kg/mm2 - Vickers
Tenacity:
Brittle
Cleavage:
Perfect
{001}
{001}
Fracture:
Irregular/Uneven
Density:
6.582 g/cm3 (Calculated)
Optical Data of Grundmannite
Type:
Anisotropic
Anisotropism:
light-brown to brown rotation tints
Bireflectance:
weak
Reflectivity:
| 470 (41.8–45.1) 546 (42.1–45.7) 589 (42.5–46.2) 650 nm | R=41.0–43.4% |
Graph shows reflectance levels at different wavelengths (in nm). Top of box is 100%. Peak reflectance is 41.0–43.4%.
Pleochroism:
Weak
Comments:
from cream to light grey
Chemical Properties of Grundmannite
Formula:
CuBiSe2
Elements listed:
Crystallography of Grundmannite
Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:
Pnma
Setting:
Pnma
Cell Parameters:
a = 6.6362(5) Å, b = 4.2581(3) Å, c = 15.3691(9) Å
Ratio:
a:b:c = 1.558 : 1 : 3.609
Unit Cell V:
434.29 ų
Z:
4
Morphology:
usually intergrown with watkinsonite and clausthalite;
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.490 | (49) |
| 3.318 | (57) |
| 3.275 | (100) |
| 2.492 | (41) |
| 2.331 | (45) |
| 2.129 | (33) |
| 1.993 | (31) |
| 1.947 | (32) |
Type Occurrence of Grundmannite
General Appearance of Type Material:
anhedral to subhedral crystals is usually in the range 50–150 μm, but may approach 250 μm
Place of Conservation of Type Material:
Type material is deposited in the mineralogical collections of the Natural History Museum, London, catalogue number BM 2015, 33.
Geological Setting of Type Material:
primary mineral, deposited from an oxidizing low-temperature hydrothermal fluid at the waning stage of selenide-mineral formation (fSe2/fS2 ratio > 1; as (1) shrinkage cracks or interstices filling and (2) independent grains within the matrix
Associated Minerals at Type Locality:
Synonyms of Grundmannite
Other Language Names for Grundmannite
Relationship of Grundmannite to other Species
Member of:
Other Members of this group:
| Chalcostibite | CuSbS2 | Orth. mmm (2/m 2/m 2/m) |
| Emplectite | CuBiS2 | Orth. mmm (2/m 2/m 2/m) : Pmna |
| Příbramite | CuSbSe2 | Orth. mmm (2/m 2/m 2/m) : Pnma |
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.
References for Grundmannite
Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Abdelghany A., Abdelmohsen N., Abou El Ela A.H., Abdelwahab D.M. (1990) Dielectric relaxation study of CuBiSe2 in the solid and liquid phases. Indian Journal of Pure and Applied Physics: 28: 329-333.
Postl, W., Paar, W.H. (1997) 1089: Selenide (Petrovicit, Watkinsonit, Clausthalit, Berzelianit, Klockmannit, Umangit) und ged. Gold bzw. Chalkosin, Bornit und Covellin von einem Forstweg südlich Altenberg a.d. Rax, Steiermark. In: Niedermayr, G. et al. (1997) Neue Mineralfunde aus Österreich XLVI. Carinthia II, 187/107, 201. [as unnamed Se analogue of emplectite]
Förster, H.-J., Bindi, L., Stanley, C.J. (2015) Grundmannite, IMA 2015-038. CNMNC Newsletter No. 26, August 2015, page 946; Mineralogical Magazine: 79: 941-947.
Förster, H. J., Bindi, L., Stanley, C. J. (2015) Grundmannite, CuBiSe2, the Se-analogue of emplectite, a new mineral from the El Dragón mine, Potosí, Bolivia. European Journal of Mineralogy, ejm2513_pap_gsw.
Internet Links for Grundmannite
mindat.org URL:
https://www.mindat.org/min-46670.html
Please feel free to link to this page.
Please feel free to link to this page.
External Links:
Mineral Dealers:
Localities for Grundmannite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for 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.
Austria | |
| Postl, W. & Paar, W.H. (1997): 1089: Selenide (Petrovicit, Watkinsonit, Clausthalit, Berzelianit, Klockmannit, Umangit) und ged. Gold bzw. Chalkosin, Bornit und Covellin von einem Forstweg südlich Altenberg a.d. Rax, Steiermark. In: Niedermayr, G. et al. (1997): Neue Mineralfunde aus Österreich XLVI. Carinthia II, 187/107, 201. [as unnamed Se analogue of emplectite] |
Bolivia (TL) | |
| Förster, H.-J., Bindi, L. and Stanley, C.J. (2015) Grundmannite, IMA 2015-038. CNMNC Newsletter No. 26, August 2015, page 946; Mineralogical Magazine, 79, 941-947.; Förster, H.-J., Bindi, L., Stanley, C.J. (2016): Grundmannite, CuBiSe2, the Se-analogue of emplectite, a new mineral from the El Dragon mine, Potosi, Bolivia. European Journal of Mineralogy, 28, 467-477.; Grundmann, G. and Förster H.-J. (2017) Origin of the El Dragón Selenium Mineralization, Quijarro Province, Potosí, Bolivia. Minerals, 7(5), 68; doi:10.3390/min7050068 |
El Dragón mine, Antonio Quijarro Province, Potosí, Bolivia