Laforetite Mineral Data

General Laforetite Information

Chemical Formula:

AgInS2

Composition:

Molecular Weight = 286.82 gm

Indium 40.03 % In

Silver 37.61 % Ag

Sulfur 22.36 % S

______

100.00 %

Empirical Formula:

AgInS₂

Environment:

Breccia vein sample from the mine dumps. Microscopic inclusions in galena.

IMA Status:

Approved IMA 1995 (Dana # Added)

Locality:

The disused Montgros mine (Pinols claim), near the hamlet La Boriette, about 10 km SW of Langeac, Haute-Loire, France. Link to MinDat.org Location Data.

Name Origin:

Named for Claude P. Laforet (1936-) a metallographer at the Bureau de Recherches Geologiques et Minieres, who first observed the mineral from the Montgros mine.

Synonym:

IMA1995-006

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Laforetite Crystallography

Axial Ratios:

a:c = 1:1.90646

Cell Dimensions:

a = 5.88, c = 11.21, Z = 4; V = 387.58 Den(Calc)= 4.92

Crystal System:

Tetragonal - ScalenohedralH-M Symbol (4 2m) Space Group: I 42d

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

By Intensity(I/I_o): 3.351(1), 2.942(0.8), 1.768(0.8),2.03(0.75), 2.082(0.75), 1.189(0.4), 1.707(0.35),

Physical Properties of Laforetite

Cleavage:

None

Color:

Brown.

Diaphaneity:

Opaque

Habit:

Inclusions - Generally found as inclusions in other minerals.

Habit:

Microscopic Crystals - Crystals visible only with microscopes.

Hardness:

3 - Calcite

Luster:

Metallic

Streak:

chocolate brown

Optical Properties of Laforetite

RL Anisotrophism:

Strong, brick-red with an orange tint to bluish-gray purplish.

RL Color:

Brownish gray in oil with abundant strawberry red internal reflections.

RL Pleochroism:

Weak, from brown to brown-gray.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Laforetite in Air**
λ	R	∑ R(λ)
480 nm	26.00
540 nm	24.60
580 nm	24.20
640 nm	24.60

**Calculated Relative Intensity Colors of Laforetite in Air**
Relative Intensity	0%	40%	80%	100%	120%	160%	200%	240%	280%	320%	360%
R

Calculated Properties of Laforetite

Electron Density:

Bulk Density (Electron Density)=4.39 gm/cc
note: Specific Gravity of Laforetite =4.92 gm/cc.

Fermion Index:

Fermion Index = 0.0016769739
Boson Index = 0.9983230261

Photoelectric:

PE_Laforetite= 213.69 barns/electron
U=PE_Laforetite x rElectron Density= 938.38 barns/cc.

Radioactivity:

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

Laforetite Classification

Dana Class:

02.09.01.06 (02)Sulfides - Including Selenides and Tellurides

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

(02.09.01)Chalcopyrite Group (Tetragonal: I-42d)

02.09.01.01 Chalcopyrite CuFeS2 I 42d 4 2m

02.09.01.02 Eskebornite CuFeSe2 I 42d 4 2m

02.09.01.03 Gallite CuGaS2 I 42d 4 2m

02.09.01.04 Roquesite CuInS2 I 42d 4 2m

02.09.01.05 Lenaite AgFeS2 P 4₂mc 4mm

02.09.01.06 Laforetite! AgInS2 I 42d 4 2m

Strunz Class:

02.CB.10a 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.10a Chalcopyrite CuFeS2 I 42d 4 2m

02.CB.10a Eskebornite CuFeSe2 I 42d 4 2m

02.CB.10a Gallite CuGaS2 I 42d 4 2m

02.CB.10a Laforetite! AgInS2 I 42d 4 2m

02.CB.10a Lenaite AgFeS2 P 4₂mc 4mm

02.CB.10a Roquesite CuInS2 I 42d 4 2m

Other Laforetite Information

References:

NAME( MinRec, Vol 31, No 4) PHYS. PROP.(MinRec, Vol 31, No 4) OPTIC PROP.(AmMin, v 85, p 875)

See Also:

Links to other databases for Laforetite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - Handbook of Mineralogy (MinSocAm)
7 - Handbook of Mineralogy (UofA)
8 - MinDAT
9 - Mineralienatlas (Deutsch)
10 - Online Mineral Museum
11 - QUT Mineral Atlas
12 - Ruff.Info

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

Laforetite

AgInS2
Dana No: 02.09.01.06 Strunz No: 02.CB.10a
Locality:

Notes: