Gebhardite Mineral Data

General Gebhardite Information

Chemical Formula:

Pb8(As+++2O5)2OCl6

Composition:

Molecular Weight = 2,346.00 gm

Arsenic 12.77 % As 16.87 % As₂O₃

Lead 70.66 % Pb 76.11 % PbO

Chlorine 9.07 % Cl 9.07 % Cl

- % Cl -2.05 % -O=Cl₂

Oxygen 7.50 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Pb₈As₄O₁₁Cl₆

Environment:

On a specimen of highly oxidized ore from the lower oxidation zone of a dolostone-hosted hydrothermal polymetallic ore deposit.

IMA Status:

Approved IMA 1983

Locality:

Tsumeb, Namibia. Link to MinDat.org Location Data.

Name Origin:

Named for Georg Gebhard (1945- ), German chemist, mineral collector, and authority on rare minerals, who supplied the specimen.

Name Pronunciation:

Gebhardite + Pronunciation

Synonym:

ICSD 40343

PDF 36-611

Gebhardite Crystallography

Axial Ratios:

a:b:c =0.6003:1:3.0526

Cell Dimensions:

a = 6.724, b = 11.2, c = 34.19, Z = 4; beta = 85.2° V = 2,565.78 Den(Calc)= 6.07

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 2₁/c

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 6.7(1), 3.68(0.8), 3.72(0.8),

Physical Properties of Gebhardite

Cleavage:

{001} Perfect, {010} Good

Color:

Light brown.

Density:

Diaphaneity:

Transparent

Hardness:

3 - Calcite

Luster:

Adamantine

Streak:

white

Optical Properties of Gebhardite

Gladstone-Dale:

CI meas= -0.081 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.069 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1812,KPDmeas= 0.1833,KC= 0.1695
Ncalc = 2.02 - 2.03

Optical Data:

Biaxial (-), a=2.08, g=2.12, bire=0.0400

Calculated Properties of Gebhardite

Electron Density:

Bulk Density (Electron Density)=5.06 gm/cc
note: Specific Gravity of Gebhardite =6.07 gm/cc.

Fermion Index:

Fermion Index = 0.15
Boson Index = 0.85

Photoelectric:

PE_Gebhardite=1,311.50 barns/electron
U=PE_Gebhardite x rElectron Density=6,637.39 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Gebhardite is Not Radioactive

Gebhardite Classification

Dana Class:

46.02.05.01 (46)Basic or Halogen-Containing Antimonites, Arsenites and Phosphites

(46.02)with miscellaneous formulae

(46.02.05)Dana Group

46.02.05.01 Gebhardite Pb8(As2O5)2OCl6 P 2₁/c 2/m

Strunz Class:

04.JB.50 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.J - Arsenites, Antimonites, Bismuthites, Sulfites,

04.JB -Arsenites, antimonites, bismuthites; with additional anions, without H2O

04.JB.50 Gebhardite Pb8(As2O5)2OCl6 P 2₁/c 2/m

Other Gebhardite Information

References:

NAME( AntBidBlaNic4) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Gebhardite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST

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Print or Cut-and-Paste your Gebhardite Specimen Label here :

Gebhardite

Pb8(As+++2O5)2OCl6
Dana No: 46.02.05.01 Strunz No: 04.JB.50
Locality:

Notes:

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