Mineralogy Database

Tokkoite Mineral Data

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General Tokkoite Information

Help on Chemical  Formula: Chemical Formula: K2Ca4[Si7O18(OH)](F,OH)
Help on Composition: Composition: Molecular Weight = 758.60 gm
   Potassium  10.31 %  K    12.42 % K2O
   Calcium    21.13 %  Ca   29.57 % CaO
   Silicon    25.92 %  Si   55.44 % SiO2
   Hydrogen    0.17 %  H     1.48 % H2O
   Oxygen     40.60 %  O
   Fluorine    1.88 %  F     1.88 % F
                -   %   F    -0.79 % -O=F2    
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: K2Ca4Si7O18(OH)1.25F0.75
Help on IMA Status: IMA Status: Approved IMA 1986
Help on Locality: Locality: Murun massif, between the Charo and Tokko rivers, Yakutia, Russia. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for the locality.
Help on Name Pronunciation: Name Pronunciation: Tokkoite Say TOKKOITE
Help on Synonym: Synonym: ICSD 67211
  PDF 40-517

Tokkoite Image

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  Tokkoite   Charoite

Comments: Yellow crystalline tokkoite intermixed with purple charoite (viewed cross-sectional to fiber direction).
Location: Murun, Aldan, Republic of Sakha, Siberia, Russia. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Tokkoite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.8343:1:0.5684
Help on Cell Dimensions: Cell Dimensions: a = 10.438, b = 12.511, c = 7.112, Z = 2; alpha = 89.92°, beta = 99.75°, gamma = 92.89° V = 914.17 Den(Calc)= 2.76
Help on Crystal System: Crystal System: Triclinic - Pinacoidal H-M Symbol ( 1) Space Group: P1
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 12.5(1), 10.3(0.45), 5.2(0.42),

Physical Properties of Tokkoite

Help on Cleavage: Cleavage: {010} Perfect, {110} Very Good
Help on Color: Color: Brownish yellow, Colorless, Light yellow.
Help on Density: Density: 2.76
Help on Diaphaneity: Diaphaneity: Transparent to Translucent
Help on Fracture: Fracture: Splintery - Thin, elongated fractures produced by intersecting good cleavages or partings (e.g. hornblende).
Help on Habit: Habit: Aggregates - Made of numerous individual crystals or clusters.
Help on Habit: Habit: Columnar - Forms columns
Help on Habit: Habit: Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)
Help on Hardness: Hardness: 4-5 - Fluorite-Apatite
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: white

Optical Properties of Tokkoite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.001 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.001 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2078,KPDmeas= 0.2078,KC= 0.2077
Ncalc = 1.57
Help on Optical Data: Optical Data: Biaxial (+), a=1.57, g=1.577, bire=0.0070, 2V(Meas)=38.

Calculated Properties of Tokkoite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.75 gm/cc
note: Specific Gravity of Tokkoite =2.76 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PETokkoite = 4.62 barns/electron
U=PETokkoite x relectron= 12.72 barns/cc.
Help on Radioactivity: Radioactivity:

GRapi = 148.20 (Gamma Ray American Petroleum Institute Units)
Concentration of Tokkoite per GRapi unit = 0.67 (%)

Estimated Radioactivity from Tokkoite - barely detectable


Tokkoite Classification

Help on  Dana Class: Dana Class: (67)Inosilicate Unbranched Chains with W>2
  (67.02)with W=5
  (67.02.01)Tinaksite group Tinaksite K2Na(Ca,Mn)2(Ti,Fe)O[Si7O18(OH)] P1,P 1 Tri Tokkoite K2Ca4[Si7O18(OH)](F,OH) P1 1 Senekevichite! CsKNaCa2TiO[Si7O18(OH)] P1 1
Help on  Strunz Class: Strunz Class: 09.DG.75 09 - SILICATES (Germanates)
  09.D - Inosilicates* Structural terminology according to Liebau (1985)
  09.DG -Inosilicates with 3-periodic single and multiple chains
09.DG.75 Tokkoite K2Ca4[Si7O18(OH)](F,OH) P1 1
09.DG.75 Tinaksite K2Na(Ca,Mn)2(Ti,Fe)O[Si7O18(OH)] P1,P 1 Tri

Other Tokkoite Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)
Help on See Also: See Also: Links to other databases for Tokkoite :
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.DG.75





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