Mineralogy Database

Franciscanite-VIII Mineral Data

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General Franciscanite-VIII Information

Help on Chemical  Formula: Chemical Formula: Mn++3(V+++++,[ ])1-x(SiO4)(O,OH)3(x=0.5)
Help on Composition: Composition: Molecular Weight = 331.88 gm
   Manganese  49.66 %  Mn   64.12 % MnO
   Vanadium    7.67 %  V    13.70 % V2O5
   Silicon     8.46 %  Si   18.10 % SiO2
   Hydrogen    0.46 %  H     4.07 % H2O
   Oxygen     33.75 %  O
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Mn2+3V5+0.5(SiO4)O1.5(OH)1.5
Help on Environment: Environment: Irregular segregations within a sheared sonolite-bearing assemblage in chert.
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-aged Franciscan Formation in California, USA..
Help on Name Pronunciation: Name Pronunciation: Franciscanite-VIII + Pronunciation Say FRANCISCANITE-VIII

Franciscanite-VIII 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 = 2; V = 276.21 Den(Calc)= 3.99
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), 3.105(0.9), 2.844(0.9),1.785(0.7), 1.538(0.5), 2.668(0.4), 3.97(0.3),

Physical Properties of Franciscanite-VIII

Help on Color: Color: Red, Reddish brown.
Help on Density: Density: 4.1
Help on Diaphaneity: Diaphaneity: Transparent to Translucent
Help on Fracture: Fracture: Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.
Help on Habit: Habit: Irregular Grains - Occurs as splotchy, anhedral crystals forming inclusions in other minerals or rocks.
Help on Hardness: Hardness: 4 - Fluorite
Help on Luster: Luster: Vitreous (Glassy)
Help on Magnetism: Magnetism: Weakly magnetic

Optical Properties of Franciscanite-VIII

Help on Dichroism (e): Dichroism (e): wine red or wine red.
Help on Dichroism (w): Dichroism (w): dark red or nearly black.
Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.056 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.03 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2176,KPDmeas= 0.2118,KC= 0.2244
Ncalc = 1.9 - 1.92
Help on Optical Data: Optical Data: Uniaxial (+), w=1.856-1.859, e=1.876-1.882, bire=0.0200-0.0230.

Calculated Properties of Franciscanite-VIII

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.80 gm/cc
note: Specific Gravity of Franciscanite-VIII =3.99 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0043065645
Boson Index = 0.9956934355
Help on Photoelectric: Photoelectric: PEFranciscanite-VIII = 14.70 barns/electron
U=PEFranciscanite-VIII x rElectron Density= 55.84 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Franciscanite-VIII is Not Radioactive

Franciscanite-VIII Classification

Help on  Dana Class: Dana Class: (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 Orebroite-VIII Mn3(Sb,Fe)SiO4(O,OH)3 P 3 3 Welinite-VIII (Mn,Mg)3(W,Mn)1-x(SiO4)(O,OH)3(x=1/3) P 3 3 Kittatinnyite Ca2Mn2MnSi2O8(OH)4•9(H2O) P 63/mmc 6/m 2/m 2/m Franciscanite-VIII Mn3(V,[])1-x(SiO4)(O,OH)3(x=0.5) 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-VIII 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-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 Franciscanite-VIII Specimen Label here :


Mn++3(V+++++,[ ])1-x(SiO4)(O,OH)3(x=0.5)
Dana No: Strunz No: 09.AF.07.5





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