Tvedalite Mineral Data

General Tvedalite Information

Chemical Formula:

(Ca,Mn++)4Be3Si6O17(OH)4•3(H2O)

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

Empirical Formula:

Ca₃Mn²⁺Be₃Si₆O₁₇(OH)₄•3(H₂O)

Environment:

In vugs in a nepheline-syenite pegmatite. Always overgrown by a crust of chiavennite.

IMA Status:

Approved IMA 1992

Locality:

Vevja larvikite quarry, Tvedalen, Brunlanes, Vestfold Co., Norway. Link to MinDat.org Location Data.

Name Origin:

Named for the type locality.

Name Pronunciation:

Tvedalite + Pronunciation

Synonym:

IMA1990-027

Tvedalite Crystallography

Axial Ratios:

a:b:c =0.377:1:0.2127

Cell Dimensions:

a = 8.724, b = 23.14, c = 4.923, Z = 2; V = 993.82 Den(Calc)= 2.56

Crystal System:

Orthorhombic Space Group: C face centered

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

By Intensity(I/I_o): 2.837(1), 11.6(0.93), 3.87(0.75),

Physical Properties of Tvedalite

Cleavage:

{???} Perfect

Color:

White, Pale gray, Beige.

Density:

2.541

Diaphaneity:

Transparent

Hardness:

4.5 - Between Fluorite and Apatite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Tvedalite

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

Optical Data:

Biaxial (?), b=1.604

Calculated Properties of Tvedalite

Electron Density:

Bulk Density (Electron Density)=2.56 gm/cc
note: Specific Gravity of Tvedalite =2.56 gm/cc.

Fermion Index:

Fermion Index = 0.04
Boson Index = 0.96

Photoelectric:

PE_Tvedalite= 4.61 barns/electron
U=PE_Tvedalite x rElectron Density= 11.81 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Tvedalite is Not Radioactive

Tvedalite Classification

Dana Class:

70.05.02.01 (70)Inosilicate Column or Tube Structures

(70.05)with chains linked by Be

(70.05.02)Dana Group

70.05.02.01 Tvedalite (Ca,Mn)4Be3Si6O17(OH)4•3(H2O) C face centered Ortho

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

References:

NAME( Dana8) PHYS. PROP.(Am.Min.,Vol.77,p438-443,1992) OPTIC PROP.(Am.Min.,Vol.77,p438-443,1992)

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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Print or Cut-and-Paste your Tvedalite Specimen Label here :

Tvedalite

(Ca,Mn++)4Be3Si6O17(OH)4•3(H2O)
Dana No: 70.05.02.01 Strunz No: 09.DF.20
Locality:

Notes:

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