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Geffroyite Mineral Data

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General Geffroyite Information

Help on Chemical  Formula: Chemical Formula: (Ag,Cu,Fe)9(Se,S)8
Help on Composition: Composition: Molecular Weight = 1,342.22 gm
   Iron       3.74 %  Fe
   Copper    12.78 %  Cu
   Silver    43.40 %  Ag
   Selenium  35.30 %  Se
   Sulfur     4.78 %  S
            ______ 
            100.00 % 
Help on Empirical Formula: Empirical Formula: Ag5.4Cu2.7Fe2+0.9Se6S2
Help on Environment: Environment: As late stage deposits in veins cutting granite. Micro-myrmikitic texture intergrowth with clausthalite and eskebornite.
Help on IMA Status: IMA Status: Approved IMA 1982
Help on Locality: Locality: From Chameane, Puy-de-Dome, France. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: To honor Jaques Geffroy, metallugist for the French Atomic Energy Commission.
Help on Name Pronunciation: Name Pronunciation: Geffroyite + Pronunciation Say GEFFROYITE
 

Geffroyite Image

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  Geffroyite

Comments: Silvery-gray grains of geffroyite to <0.5mm embedded in tan barite matrix.
Location: Moctezuma mine, Moctezuma, Sonora, Mexcio. Scale: Overall: 3 x 2 x 2 cm.
© Tom Loomis / Dakota Matrix

Geffroyite Crystallography

Help on Cell Dimensions: Cell Dimensions: a = 10.889, Z = 3; V = 1,291.11 Den(Calc)= 5.18
Help on Crystal System: Crystal System: Isometric - Hexoctahedral H-M Symbol (4/m 3 2/m) Space Group: F m3m
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 1.925(1), 3.145(0.9), 3.282(0.9),
 

Physical Properties of Geffroyite

Help on Color: Color: Bronze brown.
Help on Density: Density: 5.39
Help on Diaphaneity: Diaphaneity: Opaque
Help on Hardness: Hardness: 2.5 - Finger Nail
Help on Luster: Luster: Metallic
 

Optical Properties of Geffroyite

Help on RL Color: RL Color: Brown with a creamy tint.
Help on Reflectivity Reflectivity
Standardized Intensity (100%) Reflection Spectra of Geffroyite in Air
λ R  ∑ R(λ) 
 420 nm   19.00   
 440 nm   21.40 
 460 nm   23.50 
 480 nm   25.50 
 500 nm   27.50 
 520 nm   29.10 
 540 nm   30.10 
 560 nm   31.70 
 580 nm   32.70 
 600 nm   33.60 
 620 nm   34.40 
 640 nm   35.10 
 660 nm   35.80 
 680 nm   36.30 
 700 nm   36.90 
Calculated Relative Intensity Colors of Geffroyite in Air
Relative
Intensity
   0%   40%   80% 100% 120% 160% 200% 240% 280% 320% 360% 390%
R                        
 

Calculated Properties of Geffroyite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=4.57 gm/cc
note: Specific Gravity of Geffroyite =5.18 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.02
Boson Index = 0.98
Help on Photoelectric: Photoelectric: PEGeffroyite = 147.93 barns/electron
U=PEGeffroyite x rElectron Density= 675.39 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Geffroyite is Not Radioactive
 

Geffroyite Classification

Help on  Dana Class: Dana Class: 02.07.01.06 (02)Sulfides - Including Selenides and Tellurides
  (02.07)where Am Bn Xp, with (m+n):p=9:8
  (02.07.01)Pentalndite Group (Isometric: Fm3m)
 
02.07.01.01 Pentlandite (Fe,Ni)9S8 F m3m 4/m 3 2/m
 
02.07.01.02 Argentopentlandite Ag(Fe,Ni)8S8 F m3m 4/m 3 2/m
 
02.07.01.03 Cobaltpentlandite Co9S8 F m3m 4/m 3 2/m
 
02.07.01.04 Shadlunite (Pb,Cd)(Fe,Cu)8S8 F m3m 4/m 3 2/m
 
02.07.01.05 Manganoshadlunite (Mn,Pb)(Cu,Fe)8S8 F m3m 4/m 3 2/m
 
02.07.01.06 Geffroyite (Ag,Cu,Fe)9(Se,S)8 F m3m 4/m 3 2/m
Help on  Strunz Class: Strunz Class: 02.BB.15a 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf
  02.B - Metal Sulfides, M:S > 1:1 (mainly 2:1)
  02.BB -With Ni, Fe
 
02.BB.15a Argentopentlandite Ag(Fe,Ni)8S8 F m3m 4/m 3 2/m
 
02.BB.15a Cobaltpentlandite Co9S8 F m3m 4/m 3 2/m
 
02.BB.15a Geffroyite (Ag,Cu,Fe)9(Se,S)8 F m3m 4/m 3 2/m
 
02.BB.15a Manganoshadlunite (Mn,Pb)(Cu,Fe)8S8 F m3m 4/m 3 2/m
 
02.BB.15a Pentlandite (Fe,Ni)9S8 F m3m 4/m 3 2/m
 
02.BB.15a Shadlunite (Pb,Cd)(Fe,Cu)8S8 F m3m 4/m 3 2/m
 

Other Geffroyite Information

Help on References: References: NAME( AntBidBlaNic1) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)
Help on See Also: See Also: Links to other databases for Geffroyite :
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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Geffroyite

(Ag,Cu,Fe)9(Se,S)8
Dana No: 02.07.01.06 Strunz No: 02.BB.15a
Locality:

 

Notes:

 

 
   
 


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