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Tumchaite Mineral Data

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General Tumchaite Information

Help on Chemical  Formula: Chemical Formula: Na2(Zr,Sn)Si4O11•2(H2O)
Help on Composition: Composition: Molecular Weight = 462.51 gm
   Sodium      9.94 %  Na   13.40 % Na2O
   Zirconium  14.79 %  Zr   19.98 % ZrO2
   Silicon    24.29 %  Si   51.96 % SiO2
   Tin         5.13 %  Sn    6.52 % SnO2
   Hydrogen    0.87 %  H     7.79 % H2O
   Oxygen     44.97 %  O
             ______        ______ 
             100.00 %       99.65 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Na2Zr0.75Sn0.2Si4O11•2(H2O)
Help on Environment: Environment: From a core sample of rocks formed by the hydrothermal alteration of dolomite-calcite carbonatites. Zr-analogue of penkvilksite-1M
Help on IMA Status: IMA Status: Approved IMA 1999 (Dana # Added)
Help on Locality: Locality: Vuoriyarvi alkali-ultrabasic massif, North Karelia on the north shore of the Vuoriyarvi lake, Murmansk Region, Russia. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: The mineral is named for the river Tumcha near Vuoriyarvi massif.
Help on Synonym: Synonym: ICSD 89740

Tumchaite Image

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Comments: SEM photomicrograph of typical tumchaite crystals shaped by the prism {hkl}, and by two pinacoids {100} and {h0l}. Grains are tabular on (100), elongated along [001]. (AmMin 85:1517).
Location: Vuoriyarvi alkali-ultrabasic massif, Murmansk Region, Russia. Scale: See Image.
© American Mineralogist

Tumchaite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =1.0369:1:0.8547
Help on Cell Dimensions: Cell Dimensions: a = 9.144, b = 8.818, c = 7.537, Z = 2; beta = 113.22° V = 558.49 Den(Calc)= 2.75
Help on Crystal System: Crystal System: Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 21/c
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 8.4(1)(100), 2.691(0.9)(131), 2.902(0.9)(211),3.401(0.9)(202), 5.38(0.9)(111), 4(0.8)(111), 2.19(0.7)(313,41

Physical Properties of Tumchaite

Help on Cleavage: Cleavage: {100} Perfect
Help on Color: Color: Colorless.
Help on Density: Density: 2.78
Help on Diaphaneity: Diaphaneity: Translucent to transparent
Help on Fracture: Fracture: Brittle - Uneven - Very brittle fracture producing uneven fragments.
Help on Habit: Habit: Massive - Granular - Common texture observed in granite and other igneous rock.
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Help on Hardness: Hardness: 4.5 - Between Fluorite and Apatite
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white

Optical Properties of Tumchaite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.007 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.004 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2124,KPDmeas= 0.2101,KC= 0.2115
Ncalc = 1.58 - 1.59
Help on Optical Data: Optical Data: Biaxial (-), a=1.57, b=1.588, g=1.594, bire=0.0240

Calculated Properties of Tumchaite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.69 gm/cc
note: Specific Gravity of Tumchaite =2.75 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.03
Boson Index = 0.97
Help on Photoelectric: Photoelectric: PETumchaite = 35.05 barns/electron
U=PETumchaite x rElectron Density= 94.21 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Tumchaite is Not Radioactive

Tumchaite Classification

Help on  Dana Class: Dana Class: (70)Inosilicate Column or Tube Structures
  (70.02)with Si2O7 dimers
  (70.02.02)Dana Group Penkvilksite Na4(Ti,Zr)2[Si8O22]•4(H2O) P 21/c 2/m Tumchaite! Na2(Zr,Sn)Si4O11•2(H2O) P 21/c 2/m
Help on  Strunz Class: Strunz Class: 09.EA.60 09 - SILICATES (Germanates)
  09.E - Phyllosilicates
  09.EA -Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings
09.EA.60 Penkvilksite Na4(Ti,Zr)2[Si8O22]•4(H2O) P 21/c 2/m
09.EA.60 Tumchaite! Na2(Zr,Sn)Si4O11•2(H2O) P 21/c 2/m

Other Tumchaite Information

Help on References: References: NAME( AmMin, v 85, p 1516) PHYS. PROP.(AmMin, v 85, p 1516) OPTIC PROP.(AmMin, v 85, p 1516)
Help on See Also: See Also: Links to other databases for Tumchaite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Athena
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - MinDAT
9 - Mineralienatlas (Deutsch)
10 - Online Mineral Museum
11 - QUT Mineral Atlas
12 - Ruff.Info

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Dana No: Strunz No: 09.EA.60





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