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:
Pd8 As3
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 - Rhombohedral H-M Symbol ( 3 ) Space Group: P 3
X Ray Diffraction:
By Intensity(I/Io ): 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
R 2
∑ 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:
PEStillwaterite = 206.24 barns/electronU=PEStillwaterite x r Electron 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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Stillwaterite
Pd8As3
Dana No: 02.16.04.01 Strunz No: 02.AC.10a
Locality:
Notes:
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