Mineralogy Database

Trechmannite Mineral Data

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General Trechmannite Information

Help on Chemical  Formula: Chemical Formula: AgAsS2
Help on Composition: Composition: Molecular Weight = 246.92 gm
   Silver   43.69 %  Ag
   Arsenic  30.34 %  As
   Sulfur   25.97 %  S
           100.00 % 
Help on Empirical Formula: Empirical Formula: AgAsS2
Help on Environment: Environment: Of hydrothermal origin, in dolomite. Dimorphous with smithite.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1905
Help on Locality: Locality: Lengenbach, Binnental, Switzerland. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Charles O. Trechmenn (1851-1917), English mineralogist.
Help on Name Pronunciation: Name Pronunciation: Trechmannite + Pronunciation Say TRECHMANNITE
Help on Synonym: Synonym: ICSD 18101
  PDF 42-555

Trechmannite Image

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Comments: Dark red, trigonal pyramid crystal of trechmannite on dolomite.
Location: Lengenbach quarry, Binntal, Valais, Switzerland. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

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Comments: Red prismatic crystals of trechmannite with minor gray glossy sulfosalt (rathite?) on white dolomite.
Location: Lengenbach quarry, Binntal, Valais, Switzerland. Scale: Crystal size 0.3 mm.
© Walter Gabriel

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Comments: Colorfull assemblege of techmannite (reddish black) with orpiment (golden yellow) and realgar (reddish orange) in white dolomite.
Location: Lengenbach quarry, Binntal, Wallis, Switzerland. Scale: Picture size 3 mm.
© Tom Loomis / Dakota Matrix

Trechmannite Crystallography

Help on Axial Ratios: Axial Ratios: a:c = 1:0.65236
Help on Cell Dimensions: Cell Dimensions: a = 13.98, c = 9.12, Z = 18; V = 1,543.62 Den(Calc)= 4.78
Help on Crystal System: Crystal System: Trigonal - Hexagonal Scalenohedral H-M Symbol (3 2/m) Space Group: R 3m
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.702(1), 1.887(0.8), 3.15(0.8),
Help on Forms: Forms:

Dbl Clk - Start-Stop Rotation
RMB - Cycle Display Modes
Drag1 - Manipulate Crystal
Drag2 - Resize

S - Stereo
I - Indicies
<space> - Start-Stop Rotation
F - Fit to Screen
M - Menu

Help on Above

Forms: ( 0 3 1) ( 1 1 0) ( 1 0 1) ( 1 0 0) ( 0 0 1)

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Physical Properties of Trechmannite

Help on Cleavage: Cleavage: {1011} Good, {0001} Fair
Help on Color: Color: Scarlet red.
Help on Density: Density: 4.78
Help on Diaphaneity: Diaphaneity: Translucent
Help on Fracture: Fracture: Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.
Help on Habit: Habit: Crystalline - Fine - Occurs as well-formed fine sized crystals.
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Help on Hardness: Hardness: 1.5-2 - Talc-Gypsum
Help on Luster: Luster: Adamantine
Help on Streak: Streak: scarlet red

Optical Properties of Trechmannite

Help on Dichroism (e): Dichroism (e): nearly colorless clear.
Help on Dichroism (w): Dichroism (w): pale reddish.
Help on Optical Data: Optical Data: Uniaxial (-), e=2.4, w=2.6, bire=0.2000.
Help on RL Anisotrophism: RL Anisotrophism: Moderate (in synthetic material).
Help on RL Color: RL Color: White with a bluish cast, with orange-red internal reflections.
Help on Reflectivity Reflectivity
Standardized Intensity (100%) Reflection Spectra of Trechmannite in Air
λ R1 R2  ∑ R1(λ)   ∑ R2(λ) 
 400 nm   37.60   26.20 
 420 nm   36.90   25.70 
 440 nm   35.50   24.90 
 460 nm   33.80   23.90 
 480 nm   32.60   23.00 
 500 nm   31.60   23.40 
 520 nm   30.70   23.70 
 540 nm   29.90   23.40 
 560 nm   29.10   22.70 
 580 nm   28.50   22.10 
 600 nm   28.00   21.50 
 620 nm   27.60   21.00 
 640 nm   27.20   20.60 
 660 nm   26.90   20.30 
 680 nm   26.40   20.00 
 700 nm   26.20   19.90 
Calculated Relative Intensity Colors of Trechmannite in Air
   0%   50% 100% 150% 200% 250% 300% 350% 400% 410%

Calculated Properties of Trechmannite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=4.34 gm/cc
note: Specific Gravity of Trechmannite =4.78 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0019479447
Boson Index = 0.9980520553
Help on Photoelectric: Photoelectric: PETrechmannite = 132.86 barns/electron
U=PETrechmannite x rElectron Density= 576.11 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Trechmannite is Not Radioactive

Trechmannite Classification

Help on  Dana Class: Dana Class: (03)Sulfides - Sulfosalts
  (03.07)where z/y = 2 - (A+)i (A++)j [By Cz], A=metals, B=semi-metals, C=non-metals
  (03.07.02)Dana Group Trechmannite AgAsS2 R 3m 3 2/m
Help on  Strunz Class: Strunz Class: 02.GC.35 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf
  02.G - Sulfarsenites, sulfantimonites, sulfbismuthites
  02.GC -Poly-sulfarsenites
02.GC.35 Trechmannite AgAsS2 R 3m 3 2/m

Other Trechmannite Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(AntBidBlaNic1)
Help on See Also: See Also: Links to other databases for Trechmannite :
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.GC.35





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