Trechmannite Mineral Data

General Trechmannite Information

Chemical Formula:

AgAsS2

Composition:

Molecular Weight = 246.92 gm

Silver 43.69 % Ag

Arsenic 30.34 % As

Sulfur 25.97 % S

______

100.00 %

Empirical Formula:

AgAsS₂

Environment:

Of hydrothermal origin, in dolomite. Dimorphous with smithite.

IMA Status:

Valid Species (Pre-IMA) 1905

Locality:

Lengenbach, Binnental, Switzerland. Link to MinDat.org Location Data.

Name Origin:

Named for Charles O. Trechmenn (1851-1917), English mineralogist.

Name Pronunciation:

Trechmannite + Pronunciation

Synonym:

ICSD 18101

PDF 42-555

Trechmannite Image

Images:

Trechmannite

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

Images:

Trechmannite

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

Images:

Trechmannite

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

Axial Ratios:

a:c = 1:0.65236

Cell Dimensions:

a = 13.98, c = 9.12, Z = 18; V = 1,543.62 Den(Calc)= 4.78

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/I_o): 2.702(1), 1.887(0.8), 3.15(0.8),

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

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Physical Properties of Trechmannite

Cleavage:

{1011} Good, {0001} Fair

Color:

Scarlet red.

Density:

4.78

Diaphaneity:

Translucent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Crystalline - Fine - Occurs as well-formed fine sized crystals.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

1.5-2 - Talc-Gypsum

Luster:

Adamantine

Streak:

scarlet red

Optical Properties of Trechmannite

Dichroism (e):

nearly colorless clear.

Dichroism (w):

pale reddish.

Optical Data:

Uniaxial (-), e=2.4, w=2.6, bire=0.2000.

RL Anisotrophism:

Moderate (in synthetic material).

RL Color:

White with a bluish cast, with orange-red internal reflections.

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**
Relative Intensity	0%	50%	100%	150%	200%	250%	300%	350%	400%	410%
R₁
R₂

Calculated Properties of Trechmannite

Electron Density:

Bulk Density (Electron Density)=4.34 gm/cc
note: Specific Gravity of Trechmannite =4.78 gm/cc.

Fermion Index:

Fermion Index = 0.0019479447
Boson Index = 0.9980520553

Photoelectric:

PE_Trechmannite= 132.86 barns/electron
U=PE_Trechmannite x rElectron Density= 576.11 barns/cc.

Radioactivity:

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

Trechmannite Classification

Dana Class:

03.07.02.01 (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

03.07.02.01 Trechmannite AgAsS2 R 3m 3 2/m

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

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(AntBidBlaNic1)

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
15 - WWW-MINCRYST

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Print or Cut-and-Paste your Trechmannite Specimen Label here :

Trechmannite

AgAsS2
Dana No: 03.07.02.01 Strunz No: 02.GC.35
Locality:

Notes:

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