Guettardite Mineral Data

General Guettardite Information

Chemical Formula:

Pb(Sb,As)2S4

Composition:

Molecular Weight = 536.82 gm

Antimony 24.95 % Sb

Arsenic 12.56 % As

Lead 38.60 % Pb

Sulfur 23.89 % S

______

100.00 %

Empirical Formula:

PbSb_1.1As_0.9S₄

Environment:

Low-temperature hydrothermal origin, in marbles.

IMA Status:

Approved IMA 1967

Locality:

At Madoc, Ontario, Canada. Link to MinDat.org Location Data.

Name Origin:

Named for Jean Etienne Guettard (17-15-1786), French geologist.

Name Pronunciation:

Guettardite + Pronunciation

Synonym:

IMA1966-018

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Guettardite Crystallography

Axial Ratios:

a:b:c =2.5289:1:1.1028

Cell Dimensions:

a = 20.095, b = 7.946, c = 8.763, Z = 8; beta = 101.2° V = 1,372.58 Den(Calc)= 5.20

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/a

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

By Intensity(I/I_o): 3.52(1), 2.795(0.9), 4.19(0.5),

Physical Properties of Guettardite

Cleavage:

{001} Perfect

Color:

Grayish black.

Density:

5.31

Diaphaneity:

Opaque

Fracture:

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

Habit:

Acicular - Occurs as needle-like crystals.

Habit:

Anhedral Grains - Granular minerals without the expression of crystal shapes

Hardness:

4 - Fluorite

Luster:

Metallic

Streak:

brownish

Optical Properties of Guettardite

RL Color:

White with reddish internal reflections.

RL Pleochroism:

Relatively strong.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Guettardite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
470 nm	37.60	42.60
546 nm	36.10	41.20
589 nm	34.80	39.30
650 nm	33.80	36.70

**Calculated Relative Intensity Colors of Guettardite in Air**
Relative Intensity	0%	30%	60%	90%	100%	120%	150%	180%	210%	240%	260%
R₁
R₂

Calculated Properties of Guettardite

Electron Density:

Bulk Density (Electron Density)=4.49 gm/cc
note: Specific Gravity of Guettardite =5.20 gm/cc.

Fermion Index:

Fermion Index = 0.08
Boson Index = 0.92

Photoelectric:

PE_Guettardite= 781.87 barns/electron
U=PE_Guettardite x rElectron Density=3,511.20 barns/cc.

Radioactivity:

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

Guettardite Classification

Dana Class:

03.07.08.02 (03)Sulfides - Sulfosalts

(03.07)where z/y = 2 - (A+)i (A++)j [By Cz], A=metals, B=semi-metals, C=non-metals

(03.07.08)Sartorite Group

03.07.08.01 Sartorite PbAs2S4 P 2₁/c 2/m

03.07.08.02 Guettardite Pb(Sb,As)2S4 P 2₁/a 2/m

03.07.08.03 Twinnite Pb(Sb,As)2S4 P1 1

03.07.08.04 Marumoite! Pb32As40S92 P 2₁ 2

Strunz Class:

02.HC.05a 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf

02.H - Sulfosalts of SnS Archetype

02.HC -With only Pb

02.HC.05a Guettardite Pb(Sb,As)2S4 P 2₁/a 2/m

02.HC.05a Sartorite PbAs2S4 P 2₁/c 2/m

02.HC.05a Twinnite Pb(Sb,As)2S4 P1 1

Other Guettardite Information

References:

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

See Also:

Links to other databases for Guettardite :
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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Print or Cut-and-Paste your Guettardite Specimen Label here :

Guettardite

Pb(Sb,As)2S4
Dana No: 03.07.08.02 Strunz No: 02.HC.05a
Locality:

Notes: