Benjaminite Mineral Data + Say BENJAMINITE


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General Benjaminite Information

Help on Chemical  Formula: Chemical Formula: (Ag,Cu)3(Bi,Pb)7S12
Help on Composition: Composition: Molecular Weight = 2,134.46 gm
   Copper    2.23 %  Cu
   Silver   11.37 %  Ag
   Bismuth  48.95 %  Bi
   Lead     19.41 %  Pb
   Sulfur   18.03 %  S
           ______ 
           100.00 % 
Help on Empirical Formula: Empirical Formula: Ag2.25Cu0.75Bi5Pb2S12
Help on Environment: Environment: In a quartz vein near the contact of a soda-granite and an intrusive rhyolite.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1924
Help on Locality: Locality: Outlaw Mine, 12 miles north of Manhattan, Nye Co. Nevada, USA. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: For Dr. Marcus Benjamin (1857-1932), of the U.S. National Museum.
Help on Synonym: Synonym: ICSD 100734
  PDF 29-577
 

Benjaminite Image

Click Here for Larger Benjaminite Image in a New Browser Window Images:
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Benjaminite   Krupkaite   Friedrichite

Comments: Crystals of a mixture of friedrichite, krupkaite, and benjaminite, with quartz crystals.
Location: Estela Mine, Julcani District, Junin, Peru. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Benjaminite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =3.2754:1:4.9898
Help on Cell Dimensions: Cell Dimensions: a = 13.246, b = 4.044, c = 20.179, Z = 2; beta = 103.21° V = 1,052.32 Den(Calc)= 6.74
Help on Crystal System: Crystal System: Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/c
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.851(1), 3.427(0.8), 3.539(0.8),
Click Here for Large Benjaminite Structure Window Crystal Structure:

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Makovicky E , Mumme W G , The Canadian Mineralogist , 17 (1979) p.607-618, The crystal structure of benjaminite Cu.5Pb.4Ag2.3Bi6.8S12

 

Physical Properties of Benjaminite

Help on Cleavage: Cleavage: [hk0] Fair
Help on Color: Color: Grayish yellow, Copper.
Help on Density: Density: 6.7
Help on Diaphaniety: Diaphaniety: Opaque
Help on Hardness: Hardness: 3.5 - Copper Penny
Help on Luminescence: Luminescence: Non-fluorescent.
Help on Luster: Luster: Metallic
Help on Magnetism: Magnetism: Nonmagnetic
 

Optical Properties of Benjaminite

Help on RL Anisotrophism: RL Anisotrophism: Strong.
Help on RL Color: RL Color: Creamy white to very pale brownish.
Help on Reflectivity Reflectivity
Standardized Intensity (100%) Reflection Spectra of Benjaminite in Air
λ R1 R2  ∑ R1(λ)   ∑ R2(λ) 
 400 nm   44.20   47.20 
   
 420 nm   44.80   47.80 
 440 nm   45.20   48.60 
 460 nm   45.20   49.00 
 480 nm   45.00   49.20 
 500 nm   44.80   49.20 
 520 nm   44.50   49.00 
 540 nm   44.00   48.60 
 560 nm   43.60   48.00 
 580 nm   43.30   47.60 
 600 nm   43.10   47.20 
 620 nm   43.00   46.80 
 640 nm   42.80   46.30 
 660 nm   42.70   45.90 
 680 nm   42.60   45.60 
 700 nm   42.50   45.20 
Calculated Relative Intensity Colors of Benjaminite in Air
Relative
Intensity
   0%   30%   60%   90% 100% 120% 150% 180% 210%
R1                  
R2                  
 

Calculated Properties of Benjaminite

Help on Electron Density: Electron Density:

relectron=5.67 gm/cc
note: rBenjaminite =6.74 gm/cc.

Help on Fermion Index Fermion Index Fermion Index = 0.04425
Boson Index = 0.95575
Help on Photoelectric: Photoelectric:

PEBenjaminite =1,322.77 barns/electron
U=PEBenjaminite x relectron=7,505.95 barns/cc.

Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Benjaminite is Not Radioactive

 

Benjaminite Classification

Help on  Dana Class: Dana Class: 3.8.10.3 (3)Sulfides - Sulfosalts
  (3.8)where 1 < z/y <2 - (A+)i (A++)j [By Cz], A=metals, B=semi-metals, C=non-metals
  (3.8.10)Pavonite Group (Monoclinic: C/2c bismuth sulfosalts)
 
3.8.10.1 Pavonite (Ag,Cu)(Bi,Pb)3S5 C 2/c 2/m
 
3.8.10.2 Makovickyite Ag1.5Bi5.5S9 C 2/c 2/m
 
3.8.10.3 Benjaminite (Ag,Cu)3(Bi,Pb)7S12 C 2/c 2/m
 
3.8.10.4 Mummeite Ag3CuPbBi6S13orAg2Cu2Pb2Bi6S13 C 2/c 2/m
 
3.8.10.5 Borodaevite Ag5(Bi,Sb)9S16 C 2/c 2/m
 
3.8.10.6 Cupropavonite AgPbCu2Bi5S10 C 2/c 2/m
 
3.8.10.7 Cupromakovickyite! Cu4AgPb2Bi9S18 C 2/m 2/m
 
3.8.10.8 Kudriavite! (Cd,Pb)Bi2S4 C 2/m 2/m
Help on  Strunz Class: Strunz Class: II/E.09-10 II - Sulfides and sulphosalts
  II/E - Sulfosalts (S : As,Sb,Bi = x) Sulfosalts with predominant Silver, x = 6.0 - 1.6
  II/E.09 - Benjaminite - Kitaibelite series
 
II/E.09-05 Borodaevite Ag5(Bi,Sb)9S16 C 2/c 2/m
 
II/E.09-10 Benjaminite (Ag,Cu)3(Bi,Pb)7S12 C 2/c 2/m
 
II/E.09-20 Mummeite Ag3CuPbBi6S13orAg2Cu2Pb2Bi6S13 C 2/c 2/m
 
II/E.09-30 Pavonite (Ag,Cu)(Bi,Pb)3S5 C 2/c 2/m
 
II/E.09-40 Cupropavonite AgPbCu2Bi5S10 C 2/c 2/m
 
II/E.09-50 Kitaibelite* Ag10PbBi30S51 Mono ? Mono
 
II/E.09-60 Makovickyite Ag1.5Bi5.5S9 C 2/c 2/m
 

Other Benjaminite 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 Benjaminite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 - WWW-MINCRYST 13 -École des Mines de Paris

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

Benjaminite

(Ag,Cu)3(Bi,Pb)7S12
Dana No: 3.8.10.3 Strunz No: II/E.09-10
Locality:

 

Notes:

 

 
   
 
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