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Benjaminite Mineral Data
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General Benjaminite Information
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 Chemical Formula: |
(Ag,Cu)3(Bi,Pb)7S12 |
| Composition: |
Molecular Weight = 2,134.46 gm |
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Copper 2.23 % Cu |
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Silver 11.37 % Ag |
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Bismuth 48.95 % Bi |
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Lead 19.41 % Pb |
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Sulfur 18.03 % S |
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______ |
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100.00 % |
| Empirical Formula: |
Ag2.25Cu0.75Bi5Pb2S12 |
| Environment: |
In a quartz vein near the contact of a soda-granite and an intrusive rhyolite. |
| IMA Status: |
Valid Species (Pre-IMA) 1924 |
| Locality: |
Outlaw Mine, 12 miles north of Manhattan, Nye Co. Nevada, USA. Link to MinDat.org Location Data. |
| Name Origin: |
For Dr. Marcus Benjamin (1857-1932), of the U.S. National Museum. |
| Name Pronunciation: |
Benjaminite + Pronunciation  |
| Synonym: |
ICSD 100734 |
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PDF 29-577 |
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Benjaminite Image |
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Images:
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Benjaminite Crystallography
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| Axial Ratios: |
a:b:c =3.2754:1:4.9898 |
| Cell Dimensions: |
a = 13.246, b = 4.044, c = 20.179, Z = 2; beta = 103.21° V = 1,052.32 Den(Calc)= 6.74 |
| Crystal System: |
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/c |
| X Ray Diffraction: |
By Intensity(I/Io): 2.851(1), 3.427(0.8), 3.539(0.8), |
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Physical Properties of Benjaminite
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| Cleavage: |
{hk0} Fair |
| Color: |
Grayish yellow, Copper. |
| Density: |
6.7 |
| Diaphaneity: |
Opaque |
| Hardness: |
3.5 - Copper Penny |
| Luminescence: |
Non-fluorescent. |
| Luster: |
Metallic |
| Magnetism: |
Nonmagnetic |
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Optical Properties of Benjaminite
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| RL Anisotrophism: |
Strong. |
| RL Color: |
Creamy white to very pale brownish. |
| Reflectivity |
Standardized Intensity (100%) Reflection Spectra of Benjaminite in Air
| λ |
R1 |
R2 |
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∑ R1(λ) |
∑ R2(λ) |
| 400 nm |
44.20 |
47.20 |
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| 420 nm |
44.80 |
47.80 |
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| 440 nm |
45.20 |
48.60 |
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| 460 nm |
45.20 |
49.00 |
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| 480 nm |
45.00 |
49.20 |
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| 500 nm |
44.80 |
49.20 |
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| 520 nm |
44.50 |
49.00 |
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| 540 nm |
44.00 |
48.60 |
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| 560 nm |
43.60 |
48.00 |
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| 580 nm |
43.30 |
47.60 |
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| 600 nm |
43.10 |
47.20 |
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| 620 nm |
43.00 |
46.80 |
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| 640 nm |
42.80 |
46.30 |
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| 660 nm |
42.70 |
45.90 |
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| 680 nm |
42.60 |
45.60 |
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| 700 nm |
42.50 |
45.20 |
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Calculated Relative Intensity Colors of Benjaminite in Air
Relative
Intensity |
0% |
30% |
60% |
90% |
100% |
120% |
150% |
180% |
210% |
| R1 |
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| R2 |
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Calculated Properties of Benjaminite
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| Electron Density: |
Bulk Density (Electron Density)=5.67 gm/cc
note: Specific Gravity of Benjaminite =6.74 gm/cc.
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| Fermion Index: |
Fermion Index = 0.04
Boson Index = 0.96 |
| Photoelectric: |
PEBenjaminite =1,322.77 barns/electron
U=PEBenjaminite x rElectron Density=7,505.95 barns/cc.
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| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Benjaminite is Not Radioactive |
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Benjaminite Classification
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| Dana Class: |
03.08.10.03 (03)Sulfides - Sulfosalts |
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(03.08)where 1 < z/y <2 - (A+)i (A++)j [By Cz], A=metals, B=semi-metals, C=non-metals |
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(03.08.10)Pavonite Group (Monoclinic: C/2c bismuth sulfosalts) |
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03.08.10.01 Pavonite (Ag,Cu)(Bi,Pb)3S5 C 2/c 2/m |
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03.08.10.02 Makovickyite Ag1.5Bi5.5S9 C 2/c 2/m |
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03.08.10.03 Benjaminite (Ag,Cu)3(Bi,Pb)7S12 C 2/c 2/m |
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03.08.10.04 Mummeite Cu0.58Ag3.11Pb1.10Bi6.65S13 C 2/c 2/m |
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03.08.10.05 Borodaevite Ag5(Bi,Sb)9S16 C 2/c 2/m |
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03.08.10.06 Cupropavonite AgPbCu2Bi5S10 C 2/c 2/m |
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03.08.10.07 Cupromakovickyite! Cu4AgPb2Bi9S18 C 2/m 2/m |
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03.08.10.08 Kudriavite! (Cd,Pb)Bi2S4 C 2/m 2/m |
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03.08.10.09 IMA2008-058! Ag5Bi13S22 C 2/m 2/m |
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03.08.10.10 IMA2005-036! Cu8Pb4Ag3Bi19S38 C 2/m 2/m |
| Strunz Class: |
02.JA.05e 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf |
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02.J - Sulfosalts of PbS Archetype |
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02.JA -Galena derivatives with little or no Pb |
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02.JA.05e Benjaminite (Ag,Cu)3(Bi,Pb)7S12 C 2/c 2/m |
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Other Benjaminite Information
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| References: |
NAME( AntBidBlaNic1) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1) |
| 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
15 - WWW-MINCRYST
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Benjaminite
(Ag,Cu)3(Bi,Pb)7S12
Dana No: 03.08.10.03 Strunz No: 02.JA.05e
Locality:
Notes:
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