Mineralogy Database

Benjaminite Mineral Data

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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 Name Pronunciation: Name Pronunciation: Benjaminite + Pronunciation Say BENJAMINITE
Help on Synonym: Synonym: ICSD 100734
  PDF 29-577

Benjaminite Image

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  Krupkaite   Friedrichite   Benjaminite

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 - Prismatic H-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),

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 Diaphaneity: Diaphaneity: 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
   0%   30%   60%   90% 100% 120% 150% 180% 210%

Calculated Properties of Benjaminite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=5.67 gm/cc
note: Specific Gravity of Benjaminite =6.74 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.04
Boson Index = 0.96
Help on Photoelectric: Photoelectric: PEBenjaminite =1,322.77 barns/electron
U=PEBenjaminite x rElectron Density=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: (03)Sulfides - Sulfosalts
  (03.08)where 1 < z/y <2 - (A+)i (A++)j [By Cz], A=metals, B=semi-metals, C=non-metals
  (03.08.10)Pavonite Group (Monoclinic: C/2c bismuth sulfosalts) Pavonite (Ag,Cu)(Bi,Pb)3S5 C 2/c 2/m Makovickyite Ag1.5Bi5.5S9 C 2/c 2/m Benjaminite (Ag,Cu)3(Bi,Pb)7S12 C 2/c 2/m Mummeite Cu0.58Ag3.11Pb1.10Bi6.65S13 C 2/c 2/m Borodaevite Ag5(Bi,Sb)9S16 C 2/c 2/m Cupropavonite AgPbCu2Bi5S10 C 2/c 2/m Cupromakovickyite! Cu4AgPb2Bi9S18 C 2/m 2/m Kudriavite! (Cd,Pb)Bi2S4 C 2/m 2/m IMA2008-058! Ag5Bi13S22 C 2/m 2/m IMA2005-036! Cu8Pb4Ag3Bi19S38 C 2/m 2/m
Help on  Strunz Class: Strunz Class: 02.JA.05e 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf
  02.J - Sulfosalts of PbS Archetype
  02.JA -Galena derivatives with little or no Pb
02.JA.05e Benjaminite (Ag,Cu)3(Bi,Pb)7S12 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 - 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: 02.JA.05e





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