Drysdallite Mineral Data

General Drysdallite Information

Chemical Formula:

Mo(Se,S)2

Composition:

Molecular Weight = 230.41 gm

Molybdenum 41.64 % Mo

Selenium 51.40 % Se

Sulfur 6.96 % S

______

100.00 %

Empirical Formula:

MoSe_1.5S_0.5

Environment:

In the oxidation zone of a uranium deposit in a talc schist.

IMA Status:

Approved IMA 1973

Locality:

From the Kapijimpanga uranium deposit, 16 km southeast of Solwezi, Northwestern Province, Zambia. Link to MinDat.org Location Data.

Name Origin:

For A.R. Drysdall, Director, Geological Survey of Zambia.

Name Pronunciation:

Drysdallite + Pronunciation

Drysdallite Image

Images:

Drysdallite

Comments: Metallic, black, submillimeter crystals of drysdallite approximatly 0.1 mm.
Location: Western Province, Zambia. Scale: Picthure Size 5 mm.
© Sandro Maggia/Minernet.it

Drysdallite Crystallography

Axial Ratios:

a:c = 1:3.92544

Cell Dimensions:

a = 3.286, c = 12.899, Z = 2; V = 120.62 Den(Calc)= 6.34

Crystal System:

Hexagonal - Dihexagonal DipyramidalH-M Symbol (6/m 2/m 2/m) Space Group: P 6₃/mmc

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

By Intensity(I/I_o): 2.373(1), 6.46(0.76), 2.845(0.55),

Physical Properties of Drysdallite

Cleavage:

{0001} Perfect

Color:

Grayish black.

Density:

6.25

Diaphaneity:

Opaque

Hardness:

1-1.5 - Talc or a little harder

Luster:

Metallic

Streak:

brown black

Optical Properties of Drysdallite

RL Anisotrophism:

Very strong, with colors from light bluish gray to purplish brown.

RL Color:

Grayish black with a yellowish tint.

RL Pleochroism:

Strong, white to very light gray, to pinkish gray.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Drysdallite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	17.00	38.00
420 nm	18.20	37.80
440 nm	19.40	37.60
460 nm	20.40	37.60
480 nm	21.40	37.50
500 nm	21.80	37.50
520 nm	21.80	37.40
540 nm	21.60	37.10
560 nm	21.40	36.70
580 nm	21.10	36.00
600 nm	20.80	35.50
620 nm	20.60	35.10
640 nm	20.50	35.00
660 nm	20.40	35.00
680 nm	20.40	35.20
700 nm	20.40	35.60

**Calculated Relative Intensity Colors of Drysdallite in Air**
Relative Intensity	0%	50%	100%	150%	200%	250%	300%	350%	400%	450%
R₁
R₂

Calculated Properties of Drysdallite

Electron Density:

Bulk Density (Electron Density)=5.56 gm/cc
note: Specific Gravity of Drysdallite =6.34 gm/cc.

Fermion Index:

Fermion Index = 0.14
Boson Index = 0.86

Photoelectric:

PE_Drysdallite= 114.13 barns/electron
U=PE_Drysdallite x rElectron Density= 634.35 barns/cc.

Radioactivity:

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

Drysdallite Classification

Dana Class:

02.12.10.02 (02)Sulfides - Including Selenides and Tellurides

(02.12)where Am Bn Xp, with (m+n):p=1:2

(02.12.10)Molybdenite Group

02.12.10.01 Molybdenite MoS2 P 6₃/mmc 6/m 2/m 2/m

02.12.10.02 Drysdallite Mo(Se,S)2 P 6₃/mmc 6/m 2/m 2/m

02.12.10.03 Tungstenite WS2 P 6₃/mmc 6/m 2/m 2/m

Strunz Class:

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

02.E - Metal Sulfides, M:S £ 1:2

02.EA -M:S = 1:2

02.EA.30 Drysdallite Mo(Se,S)2 P 6₃/mmc 6/m 2/m 2/m

02.EA.30 Jordisite MoS2 None

02.EA.30 Molybdenite MoS2 P 6₃/mmc 6/m 2/m 2/m

02.EA.30 Tungstenite WS2 P 6₃/mmc 6/m 2/m 2/m

Other Drysdallite Information

References:

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

See Also:

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

Drysdallite

Mo(Se,S)2
Dana No: 02.12.10.02 Strunz No: 02.EA.30
Locality:

Notes: