Selenium Mineral Data

General Selenium Information

Chemical Formula:

Composition:

Molecular Weight = 78.96 gm

Selenium 100.00 % Se

______

100.00 %

Empirical Formula:

Environment:

Low temperature due to sublimation of fumarolic vapors. Oxidation-reduction of selenium-bearing solutions in sandstone U and U-V deposits.

IMA Status:

Valid Species (Pre-IMA) 1828

Locality:

Grants District, McKinley County, New Mexico, USA. Link to MinDat.org Location Data.

Name Origin:

From the Greek, Selene, "goddess of the Moon" to contrast Tellure, "earth".

Name Pronunciation:

Selenium

Synonym:

ICSD 22251

PDF 42-1425

Selen tellurium - Mixture with tellurium

Selenium Image

Images:

Selenium

Comments: Acicular crystals of native Selenium (up to 1 cm in length).
Location: Ronneburg U deposit, Gera district, Thuringia, Germany. Scale: Specimen size 3 cm.
© Thomas Witzke / Abraxas-Verlag

Selenium Crystallography

Axial Ratios:

a:c = 1:1.13467

Cell Dimensions:

a = 4.366, c = 4.954, Z = 3; V = 81.78 Den(Calc)= 4.81

Crystal System:

Trigonal - TrapezohedralH-M Symbol (3 2) Space Group: P 3₁21,P 3₂21

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

By Intensity(I/I_o): 3(1), 3.78(0.55), 2.072(0.35),

Forms:

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Forms: ( 1 1 1) ( 1 1 0)

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Crystal Structure:

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

View Additional jPOWD Structure files for Selenium
[1] [2]

Physical Properties of Selenium

Cleavage:

{0112} Good

Color:

Gray, Purple gray, Reddish.

Density:

4.81

Diaphaneity:

Opaque

Fracture:

Flexible - Flexible fragments.

Habit:

Crystalline - Coarse - Occurs as well-formed coarse sized crystals.

Habit:

Disseminated - Occurs in small, distinct particles dispersed in matrix.

Habit:

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

Hardness:

2 - Gypsum

Luster:

Sub Metallic

Streak:

red

Optical Properties of Selenium

Dichroism (e):

cream white.

Dichroism (w):

brown.

Optical Data:

Uniaxial (+), w=3, e=4.04, bire=1.0400.

RL Anisotrophism:

Very strong.

RL Color:

White in air, darker white to grayish brown in oil, red in transmitted light.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Selenium in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	28.40	38.40
420 nm	27.40	37.80
440 nm	26.40	37.20
460 nm	25.50	36.30
480 nm	24.80	35.40
500 nm	24.30	34.70
520 nm	24.00	34.40
540 nm	24.10	34.10
560 nm	24.40	34.00
580 nm	24.80	33.90
600 nm	25.40	33.80
620 nm	25.80	33.50
640 nm	26.00	33.30
660 nm	25.80	32.90
680 nm	25.20	32.40
700 nm	24.60	31.90

**Calculated Relative Intensity Colors of Selenium in Air**
Relative Intensity	0%	40%	80%	100%	120%	160%	200%	240%	280%	320%	360%
R₁
R₂

Calculated Properties of Selenium

Electron Density:

Bulk Density (Electron Density)=4.14 gm/cc
note: Specific Gravity of Selenium =4.81 gm/cc.

Fermion Index:

Fermion Index = 0.07
Boson Index = 0.93

Photoelectric:

PE_Selenium= 81.52 barns/electron
U=PE_Selenium x rElectron Density= 337.68 barns/cc.

Radioactivity:

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

Selenium Classification

Dana Class:

01.03.04.01 (01)Native Elements

(01.03)with semi-metallic and non-metallic elements

(01.03.04)Dana Group

01.03.04.01 Selenium Se P 3₁21,P 3₂21 3 2

01.03.04.02 Tellurium Te P 3₁21 3 2

Strunz Class:

01.CC.10 01 - ELEMENTS (Metals and intermetallic alloys; metalloids and nonmetals; carbides, silicides, nitrides, phosphides)

01.C - Metalloids and Nonmetals

01.CC -Sulfur-selenium-iodine

01.CC.10 Selenium Se P 3₁21,P 3₂21 3 2

01.CC.10 Tellurium Te P 3₁21 3 2

Other Selenium Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)

See Also:

Links to other databases for Selenium :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - EUROmin Project
5 - Ecole des Mines de Paris
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - QUT Mineral Atlas
15 - Ruff.Info
16 - WWW-MINCRYST

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Ask about Selenium 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 Selenium Specimen Label here :

Selenium

Se
Dana No: 01.03.04.01 Strunz No: 01.CC.10
Locality:

Notes: