Franciscanite-III Mineral Data

General Franciscanite-III Information

Chemical Formula:

Mn++6V+++++2Si2(O,OH)14

Composition:

Molecular Weight = 713.69 gm

Manganese 46.19 % Mn 59.64 % MnO

Vanadium 14.28 % V 25.48 % V₂O₅

Silicon 7.87 % Si 16.84 % SiO₂

Hydrogen 0.28 % H 2.52 % H₂O

Oxygen 31.39 % O

______ ______

100.00 % 104.48 % = TOTAL OXIDE

Empirical Formula:

Mn²⁺₆V⁵⁺₂Si₂O₁₂(OH)₂

IMA Status:

Approved IMA 1986

Locality:

Pennsylvania mine, SW side of San Antonio Valley, 4 miles ENE of Mount Halilton, Santa Clara Co. California. Link to MinDat.org Location Data.

Name Origin:

Named after the Miocene age Franciscan Formation.

Name Pronunciation:

Franciscanite-III + Pronunciation

Franciscanite-III Image

Images:

Franciscanite-III

Comments: Dark reddish brown large franciscanite grains to 1.5cm in tan-colored gageite matrix.
Location: Pennsylvania mine, Santa Clara Co., California, USA. Scale: 5.5 x 4 x 3cm.
© Tom Loomis / Dakota Matrix

Franciscanite-III Crystallography

Axial Ratios:

a:c = 1:0.58959

Cell Dimensions:

a = 8.148, c = 4.804, Z = 1; V = 276.21 Den(Calc)= 4.29

Crystal System:

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

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

By Intensity(I/I_o): 2.331(1), 2.844(0.9), 3.105(0.9),

Physical Properties of Franciscanite-III

Color:

Red.

Density:

4.1

Diaphaneity:

Transparent to Translucent

Hardness:

4 - Fluorite

Luster:

Vitreous (Glassy)

Optical Properties of Franciscanite-III

Gladstone-Dale:

CI meas= 0.146 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.184 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2022,KPDmeas= 0.2116,KC= 0.2477
Ncalc = 2.02 - 2.06

Optical Data:

Uniaxial (+), w=1.859, e=1.876, bire=0.0170.

Calculated Properties of Franciscanite-III

Electron Density:

Bulk Density (Electron Density)=3.88 gm/cc
note: Specific Gravity of Franciscanite-III =4.10 gm/cc.

Fermion Index:

Fermion Index = 0.0041834865
Boson Index = 0.9958165135

Photoelectric:

PE_{Franciscanite-III}= 15.10 barns/electron
U=PE_{Franciscanite-III} x rElectron Density= 58.64 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Franciscanite-III is Not Radioactive

Franciscanite-III Classification

Dana Class:

07.03.01.02 (07)Multiple Oxides

(07.03)with 2+ and higher charged cations

(07.03.01)containing Mn (Hexagonal, P3)

07.03.01.01 Welinite-III Mn6(W,Mg)2Si2(O,OH)14 P 3 3

07.03.01.02 Franciscanite-III Mn6V2Si2(O,OH)14 P 3 3

07.03.01.03 Orebroite-III Mn6(Fe,Sb)2Si2(O,OH)14 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 Franciscanite-III Information

References:

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

See Also:

Links to other databases for Franciscanite-III :
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 Franciscanite-III Specimen Label here :

Franciscanite-III

Mn++6V+++++2Si2(O,OH)14
Dana No: 07.03.01.02 Strunz No: 09.AF.07.5
Locality:

Notes: