Laffittite Mineral Data

General Laffittite Information

Chemical Formula:

AgHgAsS3

Composition:

Molecular Weight = 479.58 gm

Silver 22.49 % Ag

Mercury 41.83 % Hg

Arsenic 15.62 % As

Sulfur 20.06 % S

______

100.00 %

Empirical Formula:

AgHgAsS₃

Environment:

In a hydrothermal deposit with other arsenic sulfides.

IMA Status:

Approved IMA 1974

Locality:

Jas Roux, Valgaudemar, Hautes-Alpes, Provence-Alpes-Côte d'Azur, France. Link to MinDat.org Location Data.

Name Origin:

Named for Pierre Laffitte, Director, National School of Mines, Paris, France.

Name Pronunciation:

Laffittite + Pronunciation

Synonym:

ICSD 31194

PDF 35-436

Laffittite Image

Images:

Laffittite

Comments: A short-prismatic, dark brown crystal of laffittite with red realgar and yellow orpiment.
Location: Getchell Mine, Adam Peak, Humboldt Co., Nevada, USA. Scale: Picture size 1.5 mm.
© Thomas Witzke / Abraxas-Verlag

Laffittite Crystallography

Axial Ratios:

a:b:c =0.6851:1:0.5886

Cell Dimensions:

a = 7.732, b = 11.285, c = 6.643, Z = 4; beta = 115.16° V = 524.65 Den(Calc)= 6.07

Crystal System:

Monoclinic - DomaticH-M Symbol (m) Space Group: Aa

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

By Intensity(I/I_o): 3.512(1), 3.202(0.78), 3.015(0.69),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
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S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
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Nakai I , Appleman D E , American Mineralogist , 68 (1983) p.235-244, Laffittite, AgHgAsS3: crystal structure and second occurrence from the, Getchell mine, Nevada

Physical Properties of Laffittite

Cleavage:

{???} Indistinct

Color:

Dark red.

Density:

6.07

Diaphaneity:

Translucent to Opaque

Hardness:

3.5 - Copper Penny

Luster:

Metallic

Streak:

brownish red

Optical Properties of Laffittite

RL Anisotrophism:

Strong, from light gray-blue to dark gray.

RL Color:

Bluish white with numerous purple-red internal reflections.

RL Pleochroism:

Strong.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Laffittite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	34.50	38.40
420 nm	34.60	37.70
440 nm	34.70	37.00
460 nm	34.40	36.10
480 nm	33.80	35.20
500 nm	32.90	34.30
520 nm	31.80	33.40
540 nm	30.70	32.50
560 nm	29.50	31.70
580 nm	28.60	30.80
600 nm	28.00	30.10
620 nm	27.40	29.70
640 nm	27.10	29.40
660 nm	26.80	29.40
680 nm	26.60	29.20
700 nm	26.30	28.90

**Calculated Relative Intensity Colors of Laffittite in Air**
Relative Intensity	0%	40%	80%	100%	120%	160%	200%	240%	280%	310%
R₁
R₂

Calculated Properties of Laffittite

Electron Density:

Bulk Density (Electron Density)=5.27 gm/cc
note: Specific Gravity of Laffittite =6.07 gm/cc.

Fermion Index:

Fermion Index = 0.12
Boson Index = 0.88

Photoelectric:

PE_Laffittite= 754.44 barns/electron
U=PE_Laffittite x rElectron Density=3,972.33 barns/cc.

Radioactivity:

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

Laffittite Classification

Dana Class:

03.04.10.02 (03)Sulfides - Sulfosalts

(03.04)where z/y > 3 - (A+)i (A++)j [By Cz], A=metals, B=semi-metals, C=non-metals

(03.04.10)Dana Group

03.04.10.01 Christite TlHgAsS3 P 2₁/n 2/m

03.04.10.02 Laffittite AgHgAsS3 Aa m

03.04.10.03 IMA2007-010! PbHgAs2S6 P lattice Mono

Strunz Class:

02.GA.35 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf

02.G - Sulfarsenites, sulfantimonites, sulfbismuthites

02.GA -Neso-sulfarsenites, etc., without additional S

02.GA.35 Laffittite AgHgAsS3 Aa m

Other Laffittite Information

References:

NAME( AntBidBlaNic1) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)

See Also:

Links to other databases for Laffittite :
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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Ask about Laffittite here :
Ask-A-Mineralogist from the Mineralogical Society of America
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Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Laffittite

AgHgAsS3
Dana No: 03.04.10.02 Strunz No: 02.GA.35
Locality:

Notes: