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Gebhardite

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About GebharditeHide

Georg Gebhard
Formula:
Pb8(As2O5)2OCl6
Colour:
Brown
Lustre:
Adamantine
Hardness:
3
Specific Gravity:
6 (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).
This page provides mineralogical data about Gebhardite.


Classification of GebharditeHide

Approved
First Published:
1983
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
46.2.5.1

46 : ANTIMONITES AND ARSENITES CONTAINING HYDROXYL OR HALOGEN
2 : Miscellaneous
23.10

23 : Arsenites

Physical Properties of GebharditeHide

Adamantine
Transparency:
Transparent
Colour:
Brown
Streak:
White
Hardness:
Hardness:
VHN100=80 - 180 - Vickers
Hardness Data:
Measured
Cleavage:
Perfect
{001}
Density:
6 g/cm3 (Calculated)

Optical Data of GebharditeHide

Type:
Biaxial (-)
RI values:
nα = 2.080 nγ = 2.120
Max Birefringence:
δ = 0.040
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
r < v strong

Chemical Properties of GebharditeHide

Formula:
Pb8(As2O5)2OCl6
IMA Formula:
Pb8As3+4O11Cl6

Crystallography of GebharditeHide

Crystal System:
Monoclinic
Cell Parameters:
a = 6.72 Å, b = 11.2 Å, c = 34.19 Å
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}.

Type Occurrence of GebharditeHide

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.
National Museum of Natural History, Washington, D.C., USA, 147360.
Associated Minerals at Type Locality:

Synonyms of GebharditeHide

Other Language Names for GebharditeHide

Related Minerals - Nickel-Strunz GroupingHide

4.JB.05Fetiasite(Fe3+,Fe2+,Ti)3(As2O5)O2Mon.
4.JB.10ManganarsiteMn3(As2O4)(OH)4
4.JB.15MagnussoniteMn10As6O18(OH,Cl)2Iso. m3m (4/m 3 2/m) : Ia3d
4.JB.15UM1984-09-AsO:ClHMnMn10As6O18(OH)ClTet. 4/mmm (4/m 2/m 2/m) : I41/acd
4.JB.20ArmangiteMn2+26(AsO3)14(HAsO3)4(CO3)Trig. 3 : P3
4.JB.25NanlingiteNa(Ca5Li)Mg12(AsO3)2[Fe(AsO3)6]F14Trig.
4.JB.30AsbecasiteCa3(Ti,Sn4+)Be2(AsO3)6(SiO4)2Trig. 3m : P3c1
4.JB.35StenhuggariteCaFeSb(AsO3)2OTet.
4.JB.40TrigonitePb3Mn2+(AsO3)2(HAsO3)Mon. m
4.JB.45FinnemanitePb5(AsO3)3ClHex. 6/m : P63/m
4.JB.55DerbyliteFe3+4Ti3Sb3+O13(OH)Mon. 2/m : P21/m
4.JB.55Tomichite(V,Fe)4Ti3AsO13(OH)Mon.
4.JB.55Graeserite(Fe3+ ,Ti)4Ti3AsO13(OH)Mon.
4.JB.60Hemloite(Ti,V3+,Fe3+,Al)12(As3+,Sb3+)2O23(OH)Tric. 1 : P1
4.JB.65FreediteCu+Pb8(AsO3)2O3Cl5Mon. 2/m : B2/m
4.JB.70GeorgiadèsitePb4(AsO3)Cl4(OH)Mon.
4.JB.75Ekatite(Fe3+,Fe2+,Zn)12(AsO3)6(AsO3,HSiO4)2(OH)6Hex.

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

23.2NanlingiteNa(Ca5Li)Mg12(AsO3)2[Fe(AsO3)6]F14Trig.
23.3LeiteiteZn(As2O4)Mon. 2/m : P21/b
23.5Kuznetsovite(Hg+2)Hg2+(AsO4)ClIso. 2 3 : P21 3
23.6PaulmooreitePb2[As2O5]Mon. 2/m : P21/b
23.7EcdemitePb6Cl4(As2O7)Tet.
23.8HeliophyllitePb6Cl4(As2O7)Orth.
23.9FinnemanitePb5(AsO3)3ClHex. 6/m : P63/m
23.11Zimbabweite(Na,K)2PbAs4(Ta,Nb,Ti)4O18Orth.
23.13RouseitePb2Mn2+[AsO3]2 · 2H2OTric.
23.14FreediteCu+Pb8(AsO3)2O3Cl5Mon. 2/m : B2/m
23.15ManganarsiteMn3(As2O4)(OH)4
23.17ArmangiteMn2+26(AsO3)14(HAsO3)4(CO3)Trig. 3 : P3
23.18KaribibiteFe3+3(As3+O2)4(As3+2O5)(OH)Orth. mmm (2/m 2/m 2/m) : Pnma
23.19SchneiderhöhniteFe2+Fe3+3As3+5O13Tric. 1 : P1
23.20Lazarenkoite(Ca,Fe2+)Fe3+As3+3O7 · 3H2OOrth.
23.21StenhuggariteCaFeSb(AsO3)2OTet.
23.22Tomichite(V,Fe)4Ti3AsO13(OH)Mon.

Other InformationHide

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 GebharditeHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Klaska, R., Gebert, W. (1982) Polytypie und struktur von gebhardit - Pb8OCl6(As2O5)2. Zeitschrift für Kristallographie: 159: 75-76. (in German)
Medenbach, O., Gebert, W., Abraham, K. (1983) Gebhardit, Pb8OCl6(As2O5)2, ein neues arsenit von Tsumeb, Südwest-Afrika/Namibia. Neues Jahrbuch für Mineralogie, Monatshefte: 1983: 445-450. (in German)
Dunn, P.J., Chao, G.Y., Fleischer, M., Ferraiolo, J.A., Langley, R.H., Pabst, A., Zilczer, J.A. (1985) New mineral names. American Mineralogist: 70: 214-221.

Internet Links for GebharditeHide

Localities for GebharditeHide

ⓘ - 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). 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 (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
Namibia (TL)
 
  • Oshikoto Region
    • Tsumeb
Neues Jahrb.Min.,Mh.(1983) 445-450
Mineral and/or Locality  
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