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Tacharanite Mineral Data

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General Tacharanite Information

Help on Chemical  Formula: Chemical Formula: Ca12Al2Si18O33(OH)36
Help on Composition: Composition: Molecular Weight = 2,180.68 gm
   Calcium   22.05 %  Ca   30.86 % CaO
   Aluminum   2.47 %  Al    4.68 % Al2O3
   Silicon   23.18 %  Si   49.60 % SiO2
   Hydrogen   1.66 %  H    14.87 % H2O
   Oxygen    50.62 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Ca12Al2Si18O33(OH)36
Help on Environment: Environment: In vesicles or fractures in dolorites or other basic igneous rocks.
Help on IMA Status: IMA Status: Approved IMA 1961
Help on Locality: Locality: Portree, Isle of Skye, Scotland. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named from the Gaelic "tacharan," a changeling, because on standing in air the mineral breaks down to form other compounds (not noticed by later investigators).
Help on Name Pronunciation: Name Pronunciation: Tacharanite + Pronunciation Say TACHARANITE

Tacharanite Image

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  Tacharanite   Phillipsite-Na

Comments: Spherical tacharanite aggregates on phillipsite crystals.
Location: Espalion, Aveyron, France. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Tacharanite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =4.6767:1:7.6438
Help on Cell Dimensions: Cell Dimensions: a = 17.07, b = 3.65, c = 27.9, Z = 1; beta = 114.1° V = 1,586.80 Den(Calc)= 2.28
Help on Crystal System: Crystal System: Monoclinic Space Group: A centered
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 12.7(1), 3.05(0.8), 2.89(0.7),

Physical Properties of Tacharanite

Help on Color: Color: White.
Help on Density: Density: 2.21 - 2.36, Average = 2.28
Help on Fracture: Fracture: Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).
Help on Habit: Habit: Cryptocrystalline - Occurs as crystals too small to distinguish with the naked eye.
Help on Hardness: Hardness: 5 - Apatite
Help on Luster: Luster: Earthy (Dull)
Help on Streak: Streak: white

Optical Properties of Tacharanite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= -0.012 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.014 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2314,KPDmeas= 0.2309,KC= 0.2282
Ncalc = 1.5 - 1.54
Help on Optical Data: Optical Data: Biaxial (+), a=1.518-1.525, g=1.53-1.537, bire=0.0120

Calculated Properties of Tacharanite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.32 gm/cc
note: Specific Gravity of Tacharanite =2.29 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PETacharanite = 3.66 barns/electron
U=PETacharanite x rElectron Density= 8.49 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Tacharanite is Not Radioactive

Tacharanite Classification

Help on  Dana Class: Dana Class: (72)Phyllosilicate Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
  (72.03)with 3-, 4-, or 5-membered rings and 8-membered rings
  (72.03.02)Tobermorite group (5- & 8-membered rings) Tobermorite Ca5Si6O16(OH)2•4(H2O) C 2221 2 2 2 Clinotobermorite Ca5Si6(O,OH)18•5(H2O) Cc,C 2/c Mono Plombierite Ca5H2Si6O18•6H2O B11b 2 Riversideite Ca5Si6O16(OH)2•2(H2O) B2212 2 2 2 Okenite Ca3[Si6O15]•6(H2O) P1 or P1 Tri Tacharanite Ca12Al2Si18O33(OH)36 A centered Mono Nekoite Ca3Si6O15•7(H2O) P1 1 Oyelite Ca10B2Si8O29•12(H2O) B**** Ortho
Help on  Strunz Class: Strunz Class: 09.HA.75 09 - SILICATES (Germanates)
  09.H - Unclassified Silicates
  09.HA -With alkali and alkali-earth Elements
09.HA.75 Tacharanite Ca12Al2Si18O33(OH)36 A centered Mono

Other Tacharanite Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)
Help on See Also: See Also: Links to other databases for Tacharanite :
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.HA.75





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