Tumchaite Mineral Data
General Tumchaite Information
Chemical Formula:
Na2(Zr,Sn)Si4O11•2(H2O)
Composition:
Molecular Weight = 462.51 gm
Sodium 9.94 % Na 13.40 % Na2 O
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 % H2 O
Oxygen 44.97 % O
______ ______
100.00 % 99.65 % = TOTAL OXIDE
Empirical Formula:
Na2 Zr0.75 Sn0.2 Si4 O11 •2(H2 O)
Environment:
From a core sample of rocks formed by the hydrothermal alteration of dolomite-calcite carbonatites. Zr-analogue of penkvilksite-1M
IMA Status:
Approved IMA 1999 (Dana # Added)
Locality:
Vuoriyarvi alkali-ultrabasic massif, North Karelia on the north shore of the Vuoriyarvi lake, Murmansk Region, Russia. Link to MinDat.org Location Data.
Name Origin:
The mineral is named for the river Tumcha near Vuoriyarvi massif.
Synonym:
ICSD 89740
IMA1999-041
Tumchaite Image
Images:
Tumchaite
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
Axial Ratios:
a:b:c =1.0369:1:0.8547
Cell Dimensions:
a = 9.144, b = 8.818, c = 7.537, Z = 2; beta = 113.22° V = 558.49 Den(Calc)= 2.75
Crystal System:
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 21 /c
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
Cleavage:
{100} Perfect
Color:
Colorless.
Density:
2.78
Diaphaneity:
Translucent to transparent
Fracture:
Brittle - Uneven - Very brittle fracture producing uneven fragments.
Habit:
Massive - Granular - Common texture observed in granite and other igneous rock.
Habit:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Hardness:
4.5 - Between Fluorite and Apatite
Luster:
Vitreous (Glassy)
Streak:
white
Optical Properties of Tumchaite
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
Optical Data:
Biaxial (-), a=1.57, b=1.588, g=1.594, bire=0.0240
Calculated Properties of Tumchaite
Electron Density:
Bulk Density (Electron Density)=2.69 gm/cc note: Specific Gravity of Tumchaite =2.75 gm/cc.
Fermion Index:
Fermion Index = 0.03 Boson Index = 0.97
Photoelectric:
PETumchaite = 35.05 barns/electronU=PETumchaite x r Electron Density= 94.21 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Tumchaite is Not Radioactive
Tumchaite Classification
Dana Class:
70.02.02.02 (70) Inosilicate Column or Tube Structures
(70.02) with Si2O7 dimers
(70.02.02) Dana Group
70.02.02.01 Penkvilksite Na4(Ti,Zr)2[Si8O22]•4(H2O) P 21 /c 2/m
70.02.02.02 Tumchaite ! Na2(Zr,Sn)Si4O11•2(H2O) P 21 /c 2/m
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
References:
NAME( AmMin, v 85, p 1516) PHYS. PROP.(AmMin, v 85, p 1516) OPTIC PROP.(AmMin, v 85, p 1516)
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
13 - WWW-MINCRYST
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Tumchaite
Na2(Zr,Sn)Si4O11•2(H2O)
Dana No: 70.02.02.02 Strunz No: 09.EA.60
Locality:
Notes:
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