Osmium Mineral Data

General Osmium Information

Chemical Formula:

(Os,Ir)

Composition:

Molecular Weight = 190.71 gm

Iridium 25.20 % Ir

Osmium 74.80 % Os

______

100.00 %

Empirical Formula:

Os_0.75Ir_0.25

Environment:

In magmatic segregation deposits and concentrated in placers derived from ultrabasic rocks.

IMA Status:

Valid Species (Pre-IMA) 1804

Locality:

Urals Region, Sverdlovskaya Oblast', Nizhnii Tagi, Russia. Link to MinDat.org Location Data.

Name Origin:

Named for the principle element in the composition.

Name Pronunciation:

Osmium

Synonym:

ICSD 40323

Iridosmine

Nevyanakite

PDF 41-601

Rutheniridosmium

Siserskite

Osmium Image

Images:

Osmium Cooperite Vasilite Vysotskite

Comments: BSE image taken with a SEM of the sulfide-dominant microparagenesis filling a gas vacuole. Cooperite crystal surrounded by Pd-Cu-Pt-S phase (vasilite?), vysotskite and osmium laths (white) in chalcopyrite-bornite matrix (dark). (CanMin 38:1258).
Location: Pustaya River placer deposit, situated within the Koryak-Kamchatka platinum-bearing belt of Alaskan-type intrusions in eastern Russia. Scale: See Image.
© Canadian Mineralogist

Osmium Crystallography

Axial Ratios:

a:c = 1:1.58953

Cell Dimensions:

a = 2.714, c = 4.314, Z = 2; V = 27.52 Den(Calc)= 23.01

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): 1.22(1), 2.13(1), 1.35(0.6),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

Wyckoff R W G , Crystal Structures , 1 (1963) p.7-83, Second edition. Interscience Publishers, New York, New York, Hexagonal closest packed, hcp, structure

Physical Properties of Osmium

Cleavage:

{0001} Perfect

Color:

Steel gray.

Density:

19 - 21, Average = 20

Diaphaneity:

Opaque

Fracture:

Elastic - Fragments which spring back after bending.

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Hardness:

6-7 - Orthoclase-Quartz

Luster:

Metallic

Streak:

gray

Optical Properties of Osmium

RL Anisotrophism:

Weak to moderate.

RL Color:

White, bluish gray tint.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Osmium in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	62.60	63.60
420 nm	63.20	64.20
440 nm	63.80	64.80
460 nm	64.30	65.30
480 nm	64.60	65.60
500 nm	64.80	66.00
520 nm	64.60	66.20
540 nm	64.30	66.20
560 nm	64.00	66.00
580 nm	63.50	65.70
600 nm	63.10	65.40
620 nm	62.80	65.40
640 nm	62.60	65.40
660 nm	62.40	65.50
680 nm	62.20	65.60
700 nm	62.00	65.80

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

Calculated Properties of Osmium

Electron Density:

Bulk Density (Electron Density)=18.4 gm/cc
note: Specific Gravity of Osmium =23.0 gm/cc.

Fermion Index:

Fermion Index = 0.13
Boson Index = 0.87

Photoelectric:

PE_Osmium=1,493.21 barns/electron
U=PE_Osmium x rElectron Density=27475.43 barns/cc.

Radioactivity:

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

Osmium Classification

Dana Class:

01.02.02.01 (01)Native Elements

(01.02)with platinum group metals and alloys

(01.02.02)Osmium group (Space Group P63/mmc)

01.02.02.01 Osmium (Os,Ir) P 6₃/mmc 6/m 2/m 2/m

01.02.02.02 Ruthenium (Ru,Ir,Os) P 6₃/mmc 6/m 2/m 2/m

01.02.02.03 Rutheniridosmine (Ir,Os,Ru) P 6₃/mmc 6/m 2/m 2/m

01.02.02.04 Hexaferrum! (Fe,Os,Ru,Ir) P 6₃/mmc 6/m 2/m 2/m

01.02.02.05 Hexamolybdenum! (Mo,Ru,Fe,Ir,Os) P 6₃/mmc 6/m 2/m 2/m

01.02.02.06 IMA2008-055! (Ni,Fe,Ir) P 6₃/mmc 6/m 2/m 2/m

Strunz Class:

01.AF.05 01 - ELEMENTS (Metals and intermetallic alloys; metalloids and nonmetals; carbides, silicides, nitrides, phosphides)

01.A - Metals and Intermetallic Alloys

01.AF -Platinum-group elements

01.AF.05 Osmium (Os,Ir) P 6₃/mmc 6/m 2/m 2/m

01.AF.05 Rutheniridosmine (Ir,Os,Ru) P 6₃/mmc 6/m 2/m 2/m

01.AF.05 Ruthenium (Ru,Ir,Os) P 6₃/mmc 6/m 2/m 2/m

Other Osmium Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)

See Also:

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

Osmium

(Os,Ir)
Dana No: 01.02.02.01 Strunz No: 01.AF.05
Locality:

Notes: