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Muthmannite Mineral Data
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General Muthmannite Information
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 Chemical Formula: |
AgAuTe2 |
| Composition: |
Molecular Weight = 556.88 gm |
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Silver 19.18 % Ag |
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Tellurium 46.51 % Te |
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Gold 34.31 % Au |
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______ |
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100.00 % |
| Empirical Formula: |
Au0.97Ag0.99Te2.03 |
| Environment: |
In close intergrowths with other tellurides, especially krennerite, in epithermal hydorthermal veins and in ores enriched by secondary processes. |
| IMA Status: |
Valid Species (Pre-IMA) 1911 |
| Locality: |
Sacaramb, Romania. Link to MinDat.org Location Data. |
| Name Origin: |
Named for Friedrich W. Muthmann (1861-1913), German chemist and crystallographer. |
| Name Pronunciation: |
Muthmannite + Pronunciation  |
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Muthmannite Image |
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Images:
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Muthmannite
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 |
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Muthmannite Crystallography
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| Axial Ratios: |
a:b:c =1.1595:1:1.6829 |
| Cell Dimensions: |
a = 5.124, b = 4.419, c = 7.437, Z = 2; beta = 89.96° V = 168.40 Den(Calc)= 10.98 |
| Crystal System: |
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 2/m |
| 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), |
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Physical Properties of Muthmannite
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| Cleavage: |
{???} Perfect |
| Color: |
Blackish yellow, Bronzy yellow, Grayish white. |
| Diaphaneity: |
Opaque |
| Habit: |
Massive - Uniformly indistinguishable crystals forming large masses. |
| Habit: |
Tabular - Form dimensions are thin in one direction. |
| Hardness: |
2.5 - Finger Nail |
| Luminescence: |
Non-fluorescent. |
| Luster: |
Metallic |
| Magnetism: |
Nonmagnetic |
| Streak: |
black |
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Optical Properties of Muthmannite
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| RL Anisotrophism: |
Distinct. |
| RL Bireflectance: |
Very low. |
| RL Color: |
Grayish white with no internal reflections. |
| RL Pleochroism: |
Very low. |
| Reflectivity |
Standardized Intensity (100%) Reflection Spectra of Muthmannite in Air
| λ |
R1 |
R2 |
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∑ R1(λ) |
∑ R2(λ) |
| 470 nm |
40.10 |
40.80 |
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| 550 nm |
38.30 |
38.60 |
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| 589 nm |
37.90 |
38.30 |
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| 650 nm |
37.70 |
38.10 |
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Calculated Relative Intensity Colors of Muthmannite in Air
Relative
Intensity |
0% |
30% |
60% |
90% |
100% |
120% |
150% |
180% |
210% |
240% |
| R1 |
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| R2 |
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Calculated Properties of Muthmannite
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| Electron Density: |
Bulk Density (Electron Density)=9.02 gm/cc
note: Specific Gravity of Muthmannite =11.0 gm/cc.
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| Fermion Index: |
Fermion Index = 0.03
Boson Index = 0.97 |
| Photoelectric: |
PEMuthmannite = 795.07 barns/electron
U=PEMuthmannite x rElectron Density=7,171.06 barns/cc.
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| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Muthmannite is Not Radioactive |
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Muthmannite Classification
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| Dana Class: |
02.08.25.01 (02)Sulfides - Including Selenides and Tellurides |
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(02.08)where Am Bn Xp, with (m+n):p=1:1 |
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(02.08.25)Dana Group |
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02.08.25.01 Muthmannite AgAuTe2 P 2/m 2/m |
| Strunz Class: |
02.CB.85 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf |
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02.C - Metal Sulfides, M:S = 1:1 (and similar) |
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02.CB -With Zn, Fe, Cu, Ag, Au, etc |
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02.CB.85 Muthmannite AgAuTe2 P 2/m 2/m |
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Other Muthmannite Information
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| References: |
NAME( Dana8) PHYS. PROP.(Dana, AmMin, 89:1505) OPTIC PROP.(AmMin, 89:1505) |
| 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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Print or Cut-and-Paste your Muthmannite Specimen Label here :
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Muthmannite
AgAuTe2
Dana No: 02.08.25.01 Strunz No: 02.CB.85
Locality:
Notes:
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