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Tvedalite Mineral Data

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General Tvedalite Information

Help on Chemical  Formula: Chemical Formula: (Ca,Mn++)4Be3Si6O17(OH)4•3(H2O)
Help on Composition: Composition: Molecular Weight = 764.79 gm
   Calcium    15.72 %  Ca   22.00 % CaO
   Manganese   7.18 %  Mn    9.28 % MnO
   Beryllium   3.54 %  Be    9.81 % BeO
   Silicon    22.03 %  Si   47.14 % SiO2
   Hydrogen    1.32 %  H    11.78 % H2O
   Oxygen     50.21 %  O
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Ca3Mn2+Be3Si6O17(OH)4•3(H2O)
Help on Environment: Environment: In vugs in a nepheline-syenite pegmatite. Always overgrown by a crust of chiavennite.
Help on IMA Status: IMA Status: Approved IMA 1992
Help on Locality: Locality: Vevja larvikite quarry, Tvedalen, Brunlanes, Vestfold Co., Norway. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for the type locality.
Help on Name Pronunciation: Name Pronunciation: Tvedalite + Pronunciation Say TVEDALITE
Help on Synonym: Synonym: IMA1990-027

Tvedalite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.377:1:0.2127
Help on Cell Dimensions: Cell Dimensions: a = 8.724, b = 23.14, c = 4.923, Z = 2; V = 993.82 Den(Calc)= 2.56
Help on Crystal System: Crystal System: Orthorhombic Space Group: C face centered
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.837(1), 11.6(0.93), 3.87(0.75),

Physical Properties of Tvedalite

Help on Cleavage: Cleavage: {???} Perfect
Help on Color: Color: White, Pale gray, Beige.
Help on Density: Density: 2.541
Help on Diaphaneity: Diaphaneity: Transparent
Help on Hardness: Hardness: 4.5 - Between Fluorite and Apatite
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white

Optical Properties of Tvedalite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.051 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.043 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2359,KPDmeas= 0.2377,KC= 0.2261
Ncalc = 1.57 - 1.58
Help on Optical Data: Optical Data: Biaxial (?), b=1.604

Calculated Properties of Tvedalite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.56 gm/cc
note: Specific Gravity of Tvedalite =2.56 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.04
Boson Index = 0.96
Help on Photoelectric: Photoelectric: PETvedalite = 4.61 barns/electron
U=PETvedalite x rElectron Density= 11.81 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Tvedalite is Not Radioactive

Tvedalite Classification

Help on  Dana Class: Dana Class: (70)Inosilicate Column or Tube Structures
  (70.05)with chains linked by Be
  (70.05.02)Dana Group Tvedalite (Ca,Mn)4Be3Si6O17(OH)4•3(H2O) C face centered Ortho
Help on  Strunz Class: Strunz Class: 09.DF.20 09 - SILICATES (Germanates)
  09.D - Inosilicates* Structural terminology according to Liebau (1985)
  09.DF -Inosilicates with 2-periodic multiple chains
09.DF.20 Tvedalite (Ca,Mn)4Be3Si6O17(OH)4•3(H2O) C face centered Ortho

Other Tvedalite Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Am.Min.,Vol.77,p438-443,1992) OPTIC PROP.(Am.Min.,Vol.77,p438-443,1992)
Help on See Also: See Also: Links to other databases for Tvedalite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

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Dana No: Strunz No: 09.DF.20





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