Stillwaterite Mineral Data

General Stillwaterite Information

Chemical Formula:

Pd8As3

Composition:

Molecular Weight = 1,076.12 gm

Arsenic 20.89 % As

Palladium 79.11 % Pd

______

100.00 %

Empirical Formula:

Pd₈As₃

Environment:

J-M reef in the Stillwater layered basic intrusion. J-M reef is a stratobound cumulate concentration of platinum group metals included in pyrrhotite crystals.

IMA Status:

Approved IMA 1975

Locality:

Stillwater Complex, Nye County, Montana, USA. Link to MinDat.org Location Data.

Name Origin:

Named after its locality.

Name Pronunciation:

Stillwaterite + Pronunciation

Stillwaterite Image

Images:

Stillwaterite

Comments: B&W photomicrograph of a stillwaterite grain (gray) associated with native gold. (CanMin, v13:321).
Location: Heavy mineral centrates from the Banded and Upper zones of Stillwater Complex, Montana, USA. Scale: See Image.
© Canadian Mineralogist

Stillwaterite Crystallography

Axial Ratios:

a:c = 1:1.39356

Cell Dimensions:

a = 7.399, c = 10.311, Z = 3; V = 488.85 Den(Calc)= 10.97

Crystal System:

Trigonal - RhombohedralH-M Symbol ( 3) Space Group: P 3

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

By Intensity(I/I_o): 2.115(1), 2.355(0.8), 1.351(0.5),

Physical Properties of Stillwaterite

Color:

Gray.

Density:

10.4

Diaphaneity:

Opaque

Habit:

Microscopic Crystals - Crystals visible only with microscopes.

Hardness:

4.5 - Between Fluorite and Apatite

Luster:

Metallic

Optical Properties of Stillwaterite

RL Anisotrophism:

Weak in air, dark gray to brownish gray, in oil, distinct in brownish black with a blue to yellowish.

RL Color:

Light creamy gray.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Stillwaterite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
470 nm	51.60	52.70
546 nm	52.50	53.20
589 nm	53.10	53.70
650 nm	54.40	55.00

**Calculated Relative Intensity Colors of Stillwaterite in Air**
Relative Intensity	0%	20%	40%	60%	80%	100%	120%	140%	160%	170%
R₁
R₂

Calculated Properties of Stillwaterite

Electron Density:

Bulk Density (Electron Density)=9.52 gm/cc
note: Specific Gravity of Stillwaterite =11.0 gm/cc.

Fermion Index:

Fermion Index = 0.17
Boson Index = 0.83

Photoelectric:

PE_{Stillwaterite}= 206.24 barns/electron
U=PE_{Stillwaterite} x rElectron Density=1,963.67 barns/cc.

Radioactivity:

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

Stillwaterite Classification

Dana Class:

02.16.04.01 (02)Sulfides - Including Selenides and Tellurides

(02.16)with miscellaneous formulae

(02.16.04)Dana Group

02.16.04.01 Stillwaterite Pd8As3 P 3 3

Strunz Class:

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

02.A - Simple Sulfides, Selenides, etc

02.AC -Alloys of metalloids with PGE

02.AC.10a Stillwaterite Pd8As3 P 3 3

Other Stillwaterite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(AntBidBlaNic1)

See Also:

Links to other databases for Stillwaterite :
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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Ask about Stillwaterite here :
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Mindat.org's Discussion Groups
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Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Stillwaterite

Pd8As3
Dana No: 02.16.04.01 Strunz No: 02.AC.10a
Locality:

Notes: