Grundmannite
A valid IMA mineral species
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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 in honor of Dr Günter Grundmann (b. 1947, Berlin, Germany), Technical University of Munich, Germany, in recognition of his pioneering work on the El Dragón mine.
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.
Unique Identifiers
Mindat ID:
46670
Long-form identifier:
mindat:1:1:46670:7
IMA Classification of Grundmannite
Approved
IMA Formula:
Cu1+Bi3+Se2-2
Approval year:
2015
First published:
2015
Classification of Grundmannite
2.HA.05
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
H : Sulfosalts of SnS archetype
A : With Cu, Ag, Fe (without Pb)
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
H : Sulfosalts of SnS archetype
A : With Cu, Ag, Fe (without Pb)
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 for Standard |
|---|---|---|
| Gdm | 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 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
Anisotropism:
Light-brown to brown rotation tints
Bireflectance:
weak
Reflectivity:
| Wavelength | R1 (%) | R2 (%) |
|---|---|---|
| 400nm | 40.7% | 42.3% |
| 420nm | 40.7% | 42.6% |
| 440nm | 40.8% | 42.8% |
| 460nm | 40.9% | 43.1% |
| 470nm | 41.0% | 43.4% |
| 480nm | 41.0% | 43.6% |
| 500nm | 41.2% | 44.1% |
| 520nm | 41.5% | 44.6% |
| 540nm | 41.8% | 45.0% |
| 546nm | 41.8% | 45.1% |
| 560nm | 41.9% | 45.3% |
| 580nm | 42.0% | 45.5% |
| 589nm | 42.1% | 45.7% |
| 600nm | 42.2% | 45.8% |
| 620nm | 42.3% | 46.0% |
| 640nm | 42.5% | 46.1% |
| 650nm | 42.5% | 46.2% |
| 660nm | 42.5% | 46.3% |
| 680nm | 42.5% | 46.5% |
| 700nm | 42.5% | 46.6% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 46.6%.
R1 shown in black, R2 shown in red
Internal Reflections:
None
Pleochroism:
Weak
Comments:
From cream to light grey
Chemistry of Grundmannite
Mindat Formula:
CuBiSe2
Element Weights:
Elements listed:
Crystallography of Grundmannite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/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 Å | (49) |
| 3.318 Å | (57) |
| 3.275 Å | (100) |
| 2.492 Å | (41) |
| 2.331 Å | (45) |
| 2.129 Å | (33) |
| 1.993 Å | (31) |
| 1.947 Å | (32) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) |
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 Chalcostibite Group:
| Chalcostibite | CuSbS2 | Orth. mmm(2/m2/m2/m) |
| Emplectite | CuBiS2 | Orth. mmm(2/m2/m2/m) : Pmna |
| Příbramite | CuSbSe2 | Orth. mmm(2/m2/m2/m) : Pnma |
Common Associates
Associations Based on Photo Data:
| 11 photos of Grundmannite associated with Clausthalite | PbSe |
| 11 photos of Grundmannite associated with Watkinsonite | Cu2PbBi4(Se,S,Te)8 |
| 8 photos of Grundmannite associated with Kruťaite | CuSe2 |
| 6 photos of Grundmannite associated with Penroseite | (Ni,Co,Cu)Se2 |
| 3 photos of Grundmannite associated with Native Gold | Au |
| 3 photos of Grundmannite associated with Goethite | Fe3+O(OH) |
| 3 photos of Grundmannite associated with Klockmannite | CuSe |
| 2 photos of Grundmannite associated with Favreauite | PbBiCu6O4(SeO3)4(OH) · H2O |
| 2 photos of Grundmannite associated with Eldragónite | Cu6BiSe4(Se2) |
| 1 photo of Grundmannite associated with Cerromojonite | CuPbBiSe3 |
Related Minerals - Strunz-mindat Grouping
| 2.HA.05 | Emplectite | CuBiS2 |
| 2.HA.05 | Příbramite | CuSbSe2 |
| 2.HA.05 | Hansblockite | (Cu,Hg)(Bi,Pb)Se2 |
| 2.HA.05 | Chalcostibite | CuSbS2 |
| 2.HA.10 | Miargyrite | AgSbS2 |
| 2.HA.20 | Sunshuite | FeBi2S4 |
| 2.HA.20 | Garavellite | FeSbBiS4 |
| 2.HA.20 | Berthierite | FeSb2S4 |
| 2.HA.20 | Graţianite | MnBi2S4 |
| 2.HA.20 | Clerite | MnSb2S4 |
| 2.HA.25 | Aramayoite | Ag3Sb2(Bi,Sb)S6 |
| 2.HA.25 | Baumstarkite | Ag3Sb3S6 |
| 2.HA.30 | Zhonghongite | Cu29(As,Sb)12S33 |
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 Grundmannite
mindat.org URL:
https://www.mindat.org/min-46670.html
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External Links:
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References for Grundmannite
Reference List:
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]
Hålenius, U., Hatert, F., Pasero, M., Mills, S. J. (2015) New minerals and nomenclature modifications approved in 2015, CNMNC Newsletter 26. Mineralogical Magazine, 79 (4) 941-947 doi:10.1180/minmag.2015.079.4.05
Förster, Hans-Jürgen, Bindi, Luca, Stanley, Chris J. (2016) Grundmannite, CuBiSe2, the Se-analogue of emplectite, a new mineral from the El Dragón mine, Potosí, Bolivia. European Journal of Mineralogy, 28 (2) 467-477 doi:10.1127/ejm/2016/0028-2513
Localities for Grundmannite
Showing 3 localities.
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.
Austria | |
| Postl et al. (1997) |
Bolivia (TL) | |
| Hålenius et al. (2015) +3 other references |
Canada | |
| Sparkes et al. (2016) |
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El Dragón mine, Porco Municipality, Antonio Quijarro Province, Potosí, Bolivia