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Gebhardite Mineral Data

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General Gebhardite Information

Help on Chemical  Formula: Chemical Formula: Pb8(As+++2O5)2OCl6
Help on Composition: 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
Help on Empirical Formula: Empirical Formula: Pb8As4O11Cl6
Help on Environment: Environment: On a specimen of highly oxidized ore from the lower oxidation zone of a dolostone-hosted hydrothermal polymetallic ore deposit.
Help on IMA Status: IMA Status: Approved IMA 1983
Help on Locality: Locality: Tsumeb, Namibia. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Georg Gebhard (1945- ), German chemist, mineral collector, and authority on rare minerals, who supplied the specimen.
Help on Name Pronunciation: Name Pronunciation: Gebhardite + Pronunciation Say GEBHARDITE
Help on Synonym: Synonym: ICSD 40343
  PDF 36-611

Gebhardite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.6003:1:3.0526
Help on Cell Dimensions: Cell Dimensions: a = 6.724, b = 11.2, c = 34.19, Z = 4; beta = 85.2° V = 2,565.78 Den(Calc)= 6.07
Help on Crystal System: 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/Io): 6.7(1), 3.68(0.8), 3.72(0.8),

Physical Properties of Gebhardite

Help on Cleavage: Cleavage: {001} Perfect, {010} Good
Help on Color: Color: Light brown.
Help on Density: Density: 6
Help on Diaphaneity: Diaphaneity: Transparent
Help on Hardness: Hardness: 3 - Calcite
Help on Luster: Luster: Adamantine
Help on Streak: Streak: white

Optical Properties of Gebhardite

Help on Gladstone-Dale: 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
Help on Optical Data: Optical Data: Biaxial (-), a=2.08, g=2.12, bire=0.0400

Calculated Properties of Gebhardite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=5.06 gm/cc
note: Specific Gravity of Gebhardite =6.07 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.15
Boson Index = 0.85
Help on Photoelectric: Photoelectric: PEGebhardite =1,311.50 barns/electron
U=PEGebhardite x rElectron Density=6,637.39 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Gebhardite is Not Radioactive

Gebhardite Classification

Help on  Dana Class: Dana Class: (46)Basic or Halogen-Containing Antimonites, Arsenites and Phosphites
  (46.02)with miscellaneous formulae
  (46.02.05)Dana Group Gebhardite Pb8(As2O5)2OCl6 P 21/c 2/m
Help on  Strunz Class: 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

Help on References: References: NAME( AntBidBlaNic4) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)
Help on See Also: 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

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Dana No: Strunz No: 04.JB.50





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