Smithite Mineral Data

General Smithite 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 with other Ag-As sulfides.

IMA Status:

Valid Species (Pre-IMA) 1905

Locality:

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

Name Origin:

Named for George Frederick Smith (1872-1953), crystallographer of the British Museum, London, England.

Name Pronunciation:

Smithite

Synonym:

ICSD 64984

PDF 42-554

Smithite Image

Images:

Smithite

Comments: Spheric, pseudo-hexagonal, reddish crystal of smithite with a gray sulfosalt on white dolomite.
Location: Lengenbach quarry, Binntal, Valais, Switzerland. Scale: Crystal size 0.5 mm.
© Walter Gabriel

Images:

Chabourneite Smithite

Comments: Black metallic chabourneite with conchoidal fracture, associated with yellow-red realgar and deep-red smithite.
Location: Jas Roux, Pelvoux Mt., Valgaudemar, Hautes-Alpes, Provence-Alpes-CÃ´te d'Azur, France. Scale: See Image.
© Rruff Database

Smithite Crystallography

Axial Ratios:

a:b:c =2.2164:1:1.9536

Cell Dimensions:

a = 17.2, b = 7.76, c = 15.16, Z = 24; beta = 101.2° V = 1,984.90 Den(Calc)= 4.96

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: A2/a

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

By Intensity(I/I_o): 2.82(1), 3.21(0.8), 2.72(0.6),

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Forms: ( 3 1 1) ( 3 1 1) ( 2 1 1) ( 4 1 1) ( 3 2 0) ( 1 0 1) ( 1 1 1) ( 1 0 0) ( 1 1 3) ( 5 1 1) ( 0 0 1)

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Physical Properties of Smithite

Cleavage:

{100} Perfect

Color:

Brown orange, Light red, Orange red.

Density:

4.9

Diaphaneity:

Subtranslucent to opaque

Fracture:

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

Habit:

Pseudo Hexagonal - Crystals show a hexagonal outline.

Habit:

Pyramidal - Crystals are shaped like pyramids.

Hardness:

1.5-2 - Talc-Gypsum

Luminescence:

Non-fluorescent.

Luster:

Sub Metallic

Streak:

vermilion red

Optical Properties of Smithite

Optical Data:

Biaxial (-), b=3.27, 2V(Meas)=~65.

Pleochroism (x):

slight.

Pleochroism (y):

slight.

Pleochroism (z):

slight.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Smithite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	40.70	44.00
420 nm	40.00	43.20
440 nm	39.30	42.40
460 nm	38.70	41.50
480 nm	37.90	40.40
500 nm	37.00	39.20
520 nm	36.00	38.00
540 nm	35.00	36.60
560 nm	33.80	35.40
580 nm	32.70	34.70
600 nm	32.00	34.00
620 nm	31.40	33.40
640 nm	31.00	32.90
660 nm	30.60	32.40
680 nm	30.40	31.80
700 nm	30.10	31.40

**Calculated Relative Intensity Colors of Smithite in Air**
Relative Intensity	0%	30%	60%	90%	100%	120%	150%	180%	210%	240%	270%
R₁
R₂

Calculated Properties of Smithite

Electron Density:

Bulk Density (Electron Density)=4.50 gm/cc
note: Specific Gravity of Smithite =4.96 gm/cc.

Fermion Index:

Fermion Index = 0.0019479447
Boson Index = 0.9980520553

Photoelectric:

PE_Smithite= 132.86 barns/electron
U=PE_Smithite x rElectron Density= 597.80 barns/cc.

Radioactivity:

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

Smithite Classification

Dana Class:

03.07.03.01 (03)Sulfides - Sulfosalts

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

(03.07.03)Dana Group

03.07.03.01 Smithite AgAsS2 A2/a 2/m

03.07.03.02 Miargyrite AgSbS2 C 2/c 2/m

Strunz Class:

02.GC.30 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf

02.G - Sulfarsenites, sulfantimonites, sulfbismuthites

02.GC -Poly-sulfarsenites

02.GC.30 Smithite AgAsS2 A2/a 2/m

Other Smithite Information

References:

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

See Also:

Links to other databases for Smithite :
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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Smithite

AgAsS2
Dana No: 03.07.03.01 Strunz No: 02.GC.30
Locality:

Notes:

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