Welinite-VIII Mineral Data

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General Welinite-VIII Information

Chemical Formula:

(Mn++,Mg)3(W++++++,Mn+++)1-x(SiO4)(O,OH)3 (x=1/3)

Composition:

Molecular Weight = 402.69 gm

Magnesium 1.21 % Mg 2.00 % MgO

Manganese 40.93 % Mn 52.85 % MnO

Silicon 6.97 % Si 14.92 % SiO₂

Hydrogen 0.25 % H 2.24 % H₂O

Tungsten 22.83 % W 28.79 % WO₃

Oxygen 27.81 % O

______ ______

100.00 % 100.79 % = TOTAL OXIDE

Empirical Formula:

Mn²⁺₃W_0.5Mg_0.2SiO₆(OH)

Environment:

In small amounts, as fillings in fissures with other mineral cutting hausmannite ore.

IMA Status:

Approved IMA 1967

Locality:

Langban, Varmland, Sweden. Link to MinDat.org Location Data.

Name Origin:

Named for Eric Welin, mineralogist and geochronologist, Swedish Museum of Natural History, Stockholm, Sweden.

Name Pronunciation:

Welinite-VIII

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Welinite-VIII Crystallography

Axial Ratios:

a:c = 1:0.58675

Cell Dimensions:

a = 8.155, c = 4.785, Z = 2; V = 275.59 Den(Calc)= 4.85

Crystal System:

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

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

By Intensity(I/I_o): 1.782(1), 2.332(0.8), 3.102(0.8),

Physical Properties of Welinite-VIII

Cleavage:

{001} Poor

Color:

Brown, Reddish black.

Density:

4.47

Diaphaneity:

Transparent to Translucent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Hardness:

4 - Fluorite

Luster:

Resinous

Streak:

pale reddish brown

Optical Properties of Welinite-VIII

Gladstone-Dale:

CI meas= 0.005 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.083 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1798,KPDmeas= 0.1951,KC= 0.196
Ncalc = 1.88 - 1.95

Optical Data:

Uniaxial (+), w=1.864, e=1.88, bire=0.0160.

Calculated Properties of Welinite-VIII

Electron Density:

Bulk Density (Electron Density)=4.12 gm/cc
note: Specific Gravity of Welinite-VIII =4.47 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_{Welinite-VIII}= 278.78 barns/electron
U=PE_{Welinite-VIII} x rElectron Density=1,147.45 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Welinite-VIII is Not Radioactive

Welinite-VIII Classification

Dana Class:

52.04.01.02 (52)Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O

(52.04)with cations in [6] and/or > [6] coordination

(52.04.01)Welinite group

52.04.01.01 Orebroite-VIII Mn3(Sb,Fe)SiO4(O,OH)3 P 3 3

52.04.01.02 Welinite-VIII (Mn,Mg)3(W,Mn)1-x(SiO4)(O,OH)3(x=1/3) P 3 3

52.04.01.03 Kittatinnyite Ca2Mn2MnSi2O8(OH)4•9(H2O) P 6₃/mmc 6/m 2/m 2/m

52.04.01.04 Franciscanite-VIII Mn3(V,[])1-x(SiO4)(O,OH)3(x=0.5) P 3 3

Strunz Class:

09.AF.07.5 09 - SILICATES (Germanates)

09.A - Nesosilicates

09.AF -Nesosilicates with additional anions;

09.AF.07.5 Franciscanite-III Mn6V2Si2(O,OH)14 P 3 3

09.AF.07.5 Franciscanite-VIII Mn3(V,[])1-x(SiO4)(O,OH)3(x=0.5) P 3 3

09.AF.07.5 Orebroite-III Mn6(Fe,Sb)2Si2(O,OH)14 P 3 3

09.AF.07.5 Welinite-III Mn6(W,Mg)2Si2(O,OH)14 P 3 3

09.AF.07.5 Welinite-VIII (Mn,Mg)3(W,Mn)1-x(SiO4)(O,OH)3(x=1/3) P 3 3

Other Welinite-VIII Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Welinite-VIII :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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Print or Cut-and-Paste your Welinite-VIII Specimen Label here :

Welinite-VIII

(Mn++,Mg)3(W++++++,Mn+++)1-x(SiO4)(O,OH)3 (x=1/3)
Dana No: 52.04.01.02 Strunz No: 09.AF.07.5
Locality:

Notes: