Dervillite Mineral Data

General Dervillite Information

Chemical Formula:

Ag2AsS2

Composition:

Molecular Weight = 354.79 gm

Silver 60.81 % Ag

Arsenic 21.12 % As

Sulfur 18.08 % S

______

100.00 %

Empirical Formula:

Ag₂AsS₂

Environment:

In a Co-Ni-Fe-As deposit.

IMA Status:

Valid Species (Pre-IMA) 1941

Locality:

Found on a museum specimen from the Gabe-Gottes mine, Sainte-Marie-aux-Mies, Haut-Rhin, France. Link to MinDat.org Location Data.

Name Origin:

For Dr. Henri Derville of Strasbourg University, Strasbourg, France.

Name Pronunciation:

Dervillite + Pronunciation

Dervillite Crystallography

Axial Ratios:

a:b:c =0.5283:1:0.7452

Cell Dimensions:

a = 6.833, b = 12.932, c = 9.638, Z = 4; beta = 99.53° V = 839.90 Den(Calc)= 2.81

Crystal System:

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

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

By Intensity(I/I_o): 3.075(1), 3.019(0.8), 2.843(0.5),

Physical Properties of Dervillite

Cleavage:

{???} Good

Color:

Brownish black.

Diaphaneity:

Opaque

Hardness:

1-1.5 - Talc or a little harder

Luster:

Metallic

Streak:

black

Optical Properties of Dervillite

RL Anisotrophism:

Moderate.

RL Color:

White.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Dervillite in Air**
λ	R	∑ R(λ)
400 nm	29.70
420 nm	25.60
440 nm	24.90
460 nm	24.20
480 nm	23.70
500 nm	23.50
520 nm	23.10
540 nm	22.20
560 nm	22.20
580 nm	21.90
600 nm	21.50
620 nm	21.20
640 nm	20.90
660 nm	20.60
680 nm	20.40
700 nm	20.40

**Calculated Relative Intensity Colors of Dervillite in Air**
Relative Intensity	0%	50%	100%	150%	200%	250%	300%	350%	400%	410%
R

Calculated Properties of Dervillite

Electron Density:

Bulk Density (Electron Density)=2.52 gm/cc
note: Specific Gravity of Dervillite =2.81 gm/cc.

Fermion Index:

Fermion Index = 0.0013557034
Boson Index = 0.9986442966

Photoelectric:

PE_Dervillite= 170.89 barns/electron
U=PE_Dervillite x rElectron Density= 430.40 barns/cc.

Radioactivity:

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

Dervillite Classification

Dana Class:

03.07.17.01 (03)Sulfides - Sulfosalts

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

(03.07.17)Dana Group

03.07.17.01 Dervillite Ag2AsS2 P 2/a 2/m

Strunz Class:

02.LA.10 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf

02.L - Unclassified Sulfosalts

02.LA -Without essential Pb

02.LA.10 Dervillite Ag2AsS2 P 2/a 2/m

Other Dervillite Information

References:

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

See Also:

Links to other databases for Dervillite :
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

Search for Dervillite using:

[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Dervillite :

Ask about Dervillite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Dervillite

Ag2AsS2
Dana No: 03.07.17.01 Strunz No: 02.LA.10
Locality:

Notes:

Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.