Sillenite Mineral Data

General Sillenite Information

Chemical Formula:

Bi12SiO20

Composition:

Molecular Weight = 2,855.84 gm

Silicon 0.98 % Si 2.10 % SiO₂

Bismuth 87.81 % Bi 97.90 % Bi₂O₃

Oxygen 11.20 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Bi₁₂SiO₂₀

Environment:

Associated with bismutite

IMA Status:

Valid Species (Pre-IMA) 1943

Locality:

Durango, Mexico. Link to MinDat.org Location Data.

Name Origin:

Named fo rLars Gunnar Sillen (1916-1970) of Stockholm, Sweden for his work on Bi2O3 polymorphs.

Name Pronunciation:

Sillenite + Pronunciation

Synonym:

ICSD 28443

PDF 37-485

Sillenite Image

Images:

Sillenite

Comments: Greenish to yellowish grains of sillÃ©nite in matrix.
Location: Schneeberg District, Erzgebirge, Saxony, Germany. Scale: Picture size 4 mm.
© Thomas Witzke / Abraxas-Verlag

Sillenite Crystallography

Cell Dimensions:

a = 10.184, Z = 2; V = 1,056.22 Den(Calc)= 8.98

Crystal System:

Isometric - Tetartoidal H-M Symbol (2 3) Space Group: I 23

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

By Intensity(I/I_o): 3.22(1), 1.74(0.9), 2.73(0.8),

Physical Properties of Sillenite

Color:

Brownish green, Green, Gray green, Yellow green, Olive green.

Density:

9.3

Diaphaneity:

Transparent to Translucent

Habit:

Cubic Crystals - Occurs as cubic shaped crystals.

Habit:

Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite).

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Hardness:

1-2 - Between Talc and Gypsum

Streak:

gray green

Optical Properties of Sillenite

Gladstone-Dale:

CI meas= -0.046 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.084 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.167,KPDmeas= 0.1613,KC= 0.1542
Ncalc = 2.38 - 2.43

Optical Data:

Isotropic, n=2.5.

Calculated Properties of Sillenite

Electron Density:

Bulk Density (Electron Density)=7.62 gm/cc
note: Specific Gravity of Sillenite =9.30 gm/cc.

Fermion Index:

Fermion Index = 0.0005139279
Boson Index = 0.9994860721

Photoelectric:

PE_Sillenite=1,724.73 barns/electron
U=PE_Sillenite x rElectron Density=13142.72 barns/cc.

Radioactivity:

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

Sillenite Classification

Dana Class:

04.03.12.01 (04)Simple Oxides

(04.03)with a cation charge of 3+ (A+++2 O3)

(04.03.12)Dana Group

04.03.12.01 Sillenite Bi12SiO20 I 23 2 3

Strunz Class:

04.CB.70 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.C - Metal:Oxygen = 2:3, 3:5, and Similar

04.CB -With medium-sized cations

04.CB.70 Sillenite Bi12SiO20 I 23 2 3

Other Sillenite Information

References:

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

See Also:

Links to other databases for Sillenite :
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 Sillenite Specimen Label here :

Sillenite

Bi12SiO20
Dana No: 04.03.12.01 Strunz No: 04.CB.70
Locality:

Notes:

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