Muthmannite Mineral Data

General Muthmannite Information

Chemical Formula:

AgAuTe2

Composition:

Molecular Weight = 556.88 gm

Silver 19.18 % Ag

Tellurium 46.51 % Te

Gold 34.31 % Au

______

100.00 %

Empirical Formula:

Au_0.97Ag_0.99Te_2.03

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

Muthmannite Image

Images:

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 SacarÃ®mb, Metaliferi Mountains, western Romania.. Scale: See Image.
© American Mineralogist

Muthmannite Crystallography

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 - PrismaticH-M Symbol (2/m) Space Group: P 2/m

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 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),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
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Bindi L , Cipriani C , American Mineralogist , 89 (2004) p.1505-1509, Ordered distribution of Au and Ag in the crystal structure of muthmannite,, AuAgTe2, a rare telluride from Sacarimb, Western Romania

Physical Properties of Muthmannite

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

Optical Properties of Muthmannite

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	∑ 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**
Relative Intensity	0%	30%	60%	90%	100%	120%	150%	180%	210%	240%
R₁
R₂

Calculated Properties of Muthmannite

Electron Density:

Bulk Density (Electron Density)=9.02 gm/cc
note: Specific Gravity of Muthmannite =11.0 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Muthmannite= 795.07 barns/electron
U=PE_Muthmannite x rElectron Density=7,171.06 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Muthmannite is Not Radioactive

Muthmannite Classification

Dana Class:

02.08.25.01 (02)Sulfides - Including Selenides and Tellurides

(02.08)where Am Bn Xp, with (m+n):p=1:1

(02.08.25)Dana Group

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

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

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 :

Muthmannite

AgAuTe2
Dana No: 02.08.25.01 Strunz No: 02.CB.85
Locality:

Notes: