Mineralogy Database

Muthmannite Mineral Data

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General Muthmannite Information

Help on Chemical  Formula: Chemical Formula: AgAuTe2
Help on Composition: Composition: Molecular Weight = 556.88 gm
   Silver     19.18 %  Ag
   Tellurium  46.51 %  Te
   Gold       34.31 %  Au
             100.00 % 
Help on Empirical Formula: Empirical Formula: Au0.97Ag0.99Te2.03
Help on Environment: Environment: In close intergrowths with other tellurides, especially krennerite, in epithermal hydorthermal veins and in ores enriched by secondary processes.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1911
Help on Locality: Locality: Sacaramb, Romania. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Friedrich W. Muthmann (1861-1913), German chemist and crystallographer.
Help on Name Pronunciation: Name Pronunciation: Muthmannite + Pronunciation Say MUTHMANNITE

Muthmannite Image

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Comments: Backscattered scanning electron microphotograph of muthmannite (light gray) rimming a sylvanite (dark gray) grain. (AmMin 89:1506).
Location: Museum specimen from a gold-telluride deposit of Sacarîmb, Metaliferi Mountains, western Romania.. Scale: See Image.
© American Mineralogist

Muthmannite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =1.1595:1:1.6829
Help on Cell Dimensions: Cell Dimensions: a = 5.124, b = 4.419, c = 7.437, Z = 2; beta = 89.96° V = 168.40 Den(Calc)= 10.98
Help on Crystal System: Crystal System: Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 2/m
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 3.03(1), 2.11(0.8), 2.94(0.5),1.04(0.3), 1.32(0.3), 1.7(0.3), 1.95(0.3), 5.09(0.2),

Physical Properties of Muthmannite

Help on Cleavage: Cleavage: {???} Perfect
Help on Color: Color: Blackish yellow, Bronzy yellow, Grayish white.
Help on Diaphaneity: Diaphaneity: Opaque
Help on Habit: Habit: Massive - Uniformly indistinguishable crystals forming large masses.
Help on Habit: Habit: Tabular - Form dimensions are thin in one direction.
Help on Hardness: Hardness: 2.5 - Finger Nail
Help on Luminescence: Luminescence: Non-fluorescent.
Help on Luster: Luster: Metallic
Help on Magnetism: Magnetism: Nonmagnetic
Help on Streak: Streak: black

Optical Properties of Muthmannite

Help on RL Anisotrophism: RL Anisotrophism: Distinct.
Help on RL Bireflectance: RL Bireflectance: Very low.
Help on RL Color: RL Color: Grayish white with no internal reflections.
Help on RL Pleochroism: RL Pleochroism: Very low.
Help on Reflectivity Reflectivity
Standardized Intensity (100%) Reflection Spectra of Muthmannite in Air
λ R1 R2  ∑ R1(λ)   ∑ R2(λ) 
 470 nm   40.10   40.80 
 550 nm   38.30   38.60 
 589 nm   37.90   38.30 
 650 nm   37.70   38.10 
Calculated Relative Intensity Colors of Muthmannite in Air
   0%   30%   60%   90% 100% 120% 150% 180% 210% 240%

Calculated Properties of Muthmannite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=9.02 gm/cc
note: Specific Gravity of Muthmannite =11.0 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.03
Boson Index = 0.97
Help on Photoelectric: Photoelectric: PEMuthmannite = 795.07 barns/electron
U=PEMuthmannite x rElectron Density=7,171.06 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Muthmannite is Not Radioactive

Muthmannite Classification

Help on  Dana Class: Dana Class: (02)Sulfides - Including Selenides and Tellurides
  (02.08)where Am Bn Xp, with (m+n):p=1:1
  (02.08.25)Dana Group Muthmannite AgAuTe2 P 2/m 2/m
Help on  Strunz Class: Strunz Class: 02.CB.85 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf
  02.C - Metal Sulfides, M:S = 1:1 (and similar)
  02.CB -With Zn, Fe, Cu, Ag, Au, etc
02.CB.85 Muthmannite AgAuTe2 P 2/m 2/m

Other Muthmannite Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Dana, AmMin, 89:1505) OPTIC PROP.(AmMin, 89:1505)
Help on See Also: See Also: Links to other databases for Muthmannite :
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.CB.85





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