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Demartinite Mineral Data

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General Demartinite Information

Help on Chemical  Formula: Chemical Formula: K2[SiF6]
Help on Composition: Composition: Molecular Weight = 220.26 gm
   Potassium  35.50 %  K    42.77 % K2O
   Sodium      0.21 %  Na    0.28 % Na2O
   Silicon    12.62 %  Si   27.01 % SiO2
   Fluorine   51.67 %  F    51.67 % F
                -   %   F   -21.76 % -O=F2    
             ______        ______ 
             100.00 %       99.96 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: K2Na0.02Si0.99F5.99
Help on Environment: Environment: Collected in April 2006 from a fumarole at the crater rim. Polymorphous with hieratite.
Help on IMA Status: IMA Status: Approved IMA 2006 (Dana # Added)
Help on Locality: Locality: La Fossa crater, Vulcano, Eolian Islands, Italy. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Francesco Demartin (b. 1953), who has made significant contributions to the chemistry of metallic clusters and to the crystal structure of Alpine rare-earth minerals and u ranium minerals.
Help on Synonym: Synonym: IMA2006-034

Demartinite Image

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Comments: SEM image of a tapering, hexagonal demartinite crystal. (CanMin, v45:1275).
Location: La Fossa crater, Vulcano, Eolian Islands, Italy.. Scale: See Image.
© Canadian Mineralogist

Demartinite Crystallography

Help on Axial Ratios: Axial Ratios: a:c = 1:1.63514
Help on Cell Dimensions: Cell Dimensions: a = 5.6461, c = 9.2322, Z = 2; V = 254.88 Den(Calc)= 2.87
Help on Crystal System: Crystal System: Hexagonal - Dihexagonal Pyramidal H-M Symbol (6mm) Space Group: P 63mc
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.301(1), 4.62(0.75), 2.155(0.54),4.32(0.43), 4.9(0.25), 2.358(0.22), 1.909(0.14), 1.403(0.13),

Physical Properties of Demartinite

Help on Color: Color: Colorless.
Help on Density: Density: 2.85
Help on Diaphaneity: Diaphaneity: Transparent
Help on Habit: Habit: Hexagonal - Six-sided crystal shape in cross-section or habit.
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white

Optical Properties of Demartinite

Help on Optical Data: Optical Data: Uniaxial (-), e=1.34, w=1.35, bire=0.0100.

Calculated Properties of Demartinite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.76 gm/cc
note: Specific Gravity of Demartinite =2.87 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0059377633
Boson Index = 0.9940622367
Help on Photoelectric: Photoelectric: PEDemartinite = 4.38 barns/electron
U=PEDemartinite x relectron= 12.11 barns/cc.
Help on Radioactivity: Radioactivity:

GRapi = 492.98 (Gamma Ray American Petroleum Institute Units)
Concentration of Demartinite per GRapi unit = 0.20 (%)

Estimated Radioactivity from Demartinite - barely detectable


Demartinite Classification

Help on  Dana Class: Dana Class: (11)Halide Complexes; Alumino-fluorides
  (11.05)where (A)m B (X)6
  (11.05.02)Malladrite Group Malladrite Na2SiF6 P 321 3 2 Bararite (NH4)2SiF6 R 3m 3 2/m Demartinite! K2[SiF6] P 63mc 6mm
Help on  Strunz Class: Strunz Class: 03.CH.20 03 - HALIDES
  03.C - Complex Halides
  03.CH -
03.CH.20 Demartinite! K2[SiF6] P 63mc 6mm

Other Demartinite Information

Help on References: References: NAME( CanMin, v45:1275) PHYS. PROP.(CanMin, v45:1275) OPTIC PROP.(CanMin, v45:1275)
Help on See Also: See Also: Links to other databases for Demartinite :
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: 03.CH.20





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