Laffittite Mineral Data

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.

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),

Physical Properties of Laffittite

Cleavage:

[???] Indistinct

Color:

Dark red.

Density:

6.07

Diaphaniety:

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:

r_electron=5.27 gm/cc
note: r_Laffittite=6.07 gm/cc.

Fermion Index

Fermion Index = 0.12782
Boson Index = 0.87218

Photoelectric:

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

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Laffittite is Not Radioactive

Laffittite Classification

Dana Class:

3.4.10.2 (3)Sulfides - Sulfosalts

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

(3.4.10)Dana Group

3.4.10.1 Christite TlHgAsS3 P 2₁/n 2/m

3.4.10.2 Laffittite AgHgAsS3 Aa m

Strunz Class:

II/E.12-10 II - Sulfides and sulphosalts

II/E - Sulfosalts (S : As,Sb,Bi = x) Sulfosalts with predominant Thallium and Mercury, x = 4.0 - 1.6

II/E.12 - Laffittite - Hatchite series

II/E.12-10 Laffittite AgHgAsS3 Aa m

II/E.12-20 Routhierite TlCu(Hg,Zn)2(As,Sb)2S3 I 4mm 4mm

II/E.12-25 Stalderite TlCu(Zn,Fe,Hg)2As2S6 I 42m 4 2m

II/E.12-30 Christite TlHgAsS3 P 2₁/n 2/m

II/E.12-40 Ellisite Tl3AsS3 R 3m 3m

II/E.12-45 Erniggliite Tl2SnAs2S6 P 3 3

II/E.12-60 Wallisite PbTl(Cu,Ag)As2S5 P1 1

II/E.12-70 Hatchite (Pb,Tl)2AgAs2S5 P1 or P1 1

II/E.12-80 Sicherite! TlAg2(As,Sb)3S6 Pmnb 2/m 2/m 2/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 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 - WWW-MINCRYST 13 -École des Mines de Paris

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

Laffittite

AgHgAsS3
Dana No: 3.4.10.2 Strunz No: II/E.12-10
Locality:

Notes: