Mineralogy Database

Franciscanite-III Mineral Data

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General Franciscanite-III Information

Help on Chemical  Formula: Chemical Formula: Mn++6V+++++2Si2(O,OH)14
Help on Composition: 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
Help on Empirical Formula: Empirical Formula: Mn2+6V5+2Si2O12(OH)2
Help on IMA Status: IMA Status: Approved IMA 1986
Help on Locality: 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.
Help on Name Origin: Name Origin: Named after the Miocene age Franciscan Formation.
Help on Name Pronunciation: Name Pronunciation: Franciscanite-III + Pronunciation Say FRANCISCANITE-III

Franciscanite-III Image

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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

Help on Axial Ratios: Axial Ratios: a:c = 1:0.58959
Help on Cell Dimensions: Cell Dimensions: a = 8.148, c = 4.804, Z = 1; V = 276.21 Den(Calc)= 4.29
Help on Crystal System: Crystal System: Trigonal - Pyramidal H-M Symbol (3) Space Group: P 3
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.331(1), 2.844(0.9), 3.105(0.9),

Physical Properties of Franciscanite-III

Help on Color: Color: Red.
Help on Density: Density: 4.1
Help on Diaphaneity: Diaphaneity: Transparent to Translucent
Help on Hardness: Hardness: 4 - Fluorite
Help on Luster: Luster: Vitreous (Glassy)

Optical Properties of Franciscanite-III

Help on Gladstone-Dale: 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
Help on Optical Data: Optical Data: Uniaxial (+), w=1.859, e=1.876, bire=0.0170.

Calculated Properties of Franciscanite-III

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.88 gm/cc
note: Specific Gravity of Franciscanite-III =4.10 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0041834865
Boson Index = 0.9958165135
Help on Photoelectric: Photoelectric: PEFranciscanite-III = 15.10 barns/electron
U=PEFranciscanite-III x rElectron Density= 58.64 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Franciscanite-III is Not Radioactive

Franciscanite-III Classification

Help on  Dana Class: Dana Class: (07)Multiple Oxides
  (07.03)with 2+ and higher charged cations
  (07.03.01)containing Mn (Hexagonal, P3) Welinite-III Mn6(W,Mg)2Si2(O,OH)14 P 3 3 Franciscanite-III Mn6V2Si2(O,OH)14 P 3 3 Orebroite-III Mn6(Fe,Sb)2Si2(O,OH)14 P 3 3
Help on  Strunz Class: 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

Help on References: References: NAME( MinRec) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)
Help on See Also: 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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Dana No: Strunz No: 09.AF.07.5





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