Gebhardite
A valid IMA mineral species
This page is currently not sponsored. Click here to sponsor this page.
About Gebhardite
Georg Gebhard
Formula:
Pb8(As2O5)2OCl6
Colour:
Brown
Lustre:
Adamantine
Hardness:
3
Specific Gravity:
6.0 (Calculated)
Crystal System:
Monoclinic
Name:
Named in honor of Georg Gebhard (1945 – ), German chemist, mineral collector, and authority on rare minerals, who supplied the specimen. Author of many mineral-related papers and the books Tsumeb (1991) and Tsumeb II (1999). The mineral christelite is named for his wife.
This page provides mineralogical data about Gebhardite.
Unique Identifiers
Mindat ID:
1664
Long-form identifier:
mindat:1:1:1664:9
Similar Names
| Gaebhardite | A synonym of 'Fuchsite' |
IMA Classification of Gebhardite
Classification of Gebhardite
4.JB.50
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
J : Arsenites, antimonites, bismuthites, sulfites, selenites, tellurites; iodates
B : Arsenites, antimonites, bismuthites; with additional anions, without H2O
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
J : Arsenites, antimonites, bismuthites, sulfites, selenites, tellurites; iodates
B : Arsenites, antimonites, bismuthites; with additional anions, without H2O
46.2.5.1
46 : ANTIMONITES AND ARSENITES CONTAINING HYDROXYL OR HALOGEN
2 : Miscellaneous
46 : ANTIMONITES AND ARSENITES CONTAINING HYDROXYL OR HALOGEN
2 : Miscellaneous
23.10
23 : Arsenites
23 : Arsenites
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 |
|---|---|---|
| Geb | 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 Gebhardite
Adamantine
Transparency:
Transparent
Colour:
Brown
Streak:
White
Hardness:
3 on Mohs scale
Hardness:
VHN100=80 - 180 - Vickers
Hardness Data:
Measured
Cleavage:
Perfect
{001}
{001}
Density:
6.0 g/cm3 (Calculated)
Optical Data of Gebhardite
Type:
Biaxial (-)
RI values:
nα = 2.08 nγ = 2.12
Max. Birefringence:
δ = 0.040
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Moderate
Dispersion:
r < v strong
Optical Extinction:
Z = b; X ∧ a = 3°.
Pleochroism:
Weak
Comments:
X = Y = pale brown; Z = brown
Chemistry of Gebhardite
Mindat Formula:
Pb8(As2O5)2OCl6
Element Weights:
Elements listed:
Crystallography of Gebhardite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/c
Cell Parameters:
a = 6.72 Å, b = 11.2 Å, c = 34.19 Å
β = 85.2°
β = 85.2°
Ratio:
a:b:c = 0.6 : 1 : 3.053
Unit Cell V:
2,564.25 ų (Calculated from Unit Cell)
Morphology:
Crystals elongated along [010], with {100} and {001}.
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
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) |
|---|---|---|---|---|---|---|---|
| 0010847 | Gebhardite | Klaska R, Gebert W (1982) Polytypie und struktur von gebhardit - Pb8OCl6(As2O5)2 Zeitschrift fur Kristallographie 159 75-76 |  | 1982 | Tsumeb mine, Tsumeb, Namibia | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.70 Å | (100) |
| 3.72 Å | (80) |
| 3.68 Å | (80) |
| 2.801 Å | (80) |
| 3.55 Å | (70) |
| 3.15 Å | (70) |
| 2.925 Å | (60) |
Comments:
Tsumeb, Namibia. Data from the type description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] | |
| 47g : [Halogen-bearing surface weathering minerals] | |
| 47h : [Near-surface oxidized, dehydrated minerals] |
Type Occurrence of Gebhardite
General Appearance of Type Material:
A weathered 5x5x3 cm mass of white carbonates and silicates coated with secondary minerals. Gebhardite in acicular crystals in contact with mimetite.
Place of Conservation of Type Material:
Ecole des mines, Paris, France.
National Museum of Natural History, Washington, D.C., USA, 147360.
National Museum of Natural History, Washington, D.C., USA, 147360.
Associated Minerals at Type Locality:
Synonyms of Gebhardite
Other Language Names for Gebhardite
Related Minerals - Strunz-mindat Grouping
| 4.JB. | Cuyaite | Ca2Mn3+As3+14O24Cl |
| 4.JB. | Brattforsite | Mn19(AsO 3)12Cl2 |
| 4.JB.05 | Fetiasite | (Fe3+,Fe2+,Ti)3(As2O5)O2 |
| 4.JB.10 | Manganarsite | Mn3(As2O4)(OH)4 |
| 4.JB.15 | 'UM1984-09-AsO:ClHMn' | Mn10As6O18(OH)Cl |
| 4.JB.15 | Magnussonite | Mn2+10(As3+O3)6(OH,Cl)2 |
| 4.JB.20 | Armangite | Mn2+26(AsO3)14(HAsO3)4(CO3) |
| 4.JB.25 | Nanlingite | Na(Ca5Li)Mg12(AsO3)2[Fe(AsO3)6]F14 |
| 4.JB.30 | Asbecasite | Ca3(Ti,Sn4+)Be2(AsO3)6(SiO4)2 |
| 4.JB.35 | Stenhuggarite | CaFeSb(AsO3)2O |
| 4.JB.40 | Trigonite | Pb3Mn2+(AsO3)2(HAsO3) |
| 4.JB.45 | Finnemanite | Pb5(AsO3)3Cl |
| 4.JB.55 | Graeserite | Fe3+4Ti3As3+O13(OH) |
| 4.JB.55 | Tomichite | (V,Fe)4Ti3AsO13(OH) |
| 4.JB.55 | Derbylite | Fe3+4Ti3Sb3+O13(OH) |
| 4.JB.60 | Hemloite | (Ti,V3+,Fe3+,Al)12(As3+,Sb3+)2O23(OH) |
| 4.JB.65 | Freedite | Cu+Pb8(AsO3)2O3Cl5 |
| 4.JB.70 | Georgiadesite | Pb4(As3+O3)Cl4(OH) |
| 4.JB.75 | Szklaryite | ◻Al6BAs3+3O15 |
| 4.JB.75 | Ekatite | (Fe3+,Fe2+,Zn)12(AsO3)6(AsO3,HSiO4)2(OH)6 |
| 4.JB.85 | Lepageite | Mn2+3(Fe3+7Fe2+4)O3[Sb3+5As3+8O34] |
| 4.JB.90 | Bianchiniite | Ba2(TiV)(As2O5)2OF |
Other Information
Notes:
Treatment with cold HCl or HNO3 leads to formation of tiny octahedra of As203.
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 Gebhardite
mindat.org URL:
https://www.mindat.org/min-1664.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Gebhardite
Localities for Gebhardite
Showing 1 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.
Namibia (TL) | |
| Medenbach et al. (1983) |
Quick NavTopAbout GebharditeUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesStrunz-MindatOther InformationInternet Links References Localities Locality List
Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia