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Bentorite Mineral Data

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General Bentorite Information

Help on Chemical  Formula: Chemical Formula: Ca6(Cr,Al)2(SO4)3(OH)12•26(H2O)
Help on Composition: Composition: Molecular Weight = 1,292.63 gm
   Calcium   18.60 %  Ca   26.03 % CaO
   Aluminum   1.04 %  Al    1.97 % Al2O3
   Chromium   6.03 %  Cr    8.82 % Cr2O3
   Hydrogen   4.99 %  H    44.60 % H2O
   Sulfur     7.44 %  S    18.58 % SO3
   Oxygen    61.89 %  O
            ______        ______ 
            100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Ca6Cr1.5Al0.5(SO4)3(OH)12•26(H2O)
Help on Environment: Environment: Low-temperature hydrothermal veins in black calcite�spurrite marble.
Help on IMA Status: IMA Status: Approved IMA 1980
Help on Locality: Locality: Marble quarry in the Hatrurim Formation, near the Arad-Sodom road, Negev Desert, Israel. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for Y.K. Bentor, Professor at the University of California, San Diego, California, USA, for his contributions to geology and mineralogy in Israel.
Help on Name Pronunciation: Name Pronunciation: Bentorite + Pronunciation Say BENTORITE

Bentorite Image

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Comments: Violet crystalline bentorite.
Location: Hatrurim Area, West of Dead Sea, Israel. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Bentorite Crystallography

Help on Axial Ratios: Axial Ratios: a:c = 1:0.95794
Help on Cell Dimensions: Cell Dimensions: a = 22.35, c = 21.41, Z = 8; V = 9,261.95 Den(Calc)= 1.85
Help on Crystal System: Crystal System: Hexagonal - Dihexagonal Dipyramidal H-M Symbol (6/m 2/m 2/m) Space Group: P 63/mmc
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 9.656(1), 5.592(0.4), 1.942(0.2),

Physical Properties of Bentorite

Help on Cleavage: Cleavage: {1010} Perfect
Help on Color: Color: Violet, Light violet.
Help on Density: Density: 2.025
Help on Diaphaneity: Diaphaneity: Transparent
Help on Hardness: Hardness: 2 - Gypsum
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: violet

Optical Properties of Bentorite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.116 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.033 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.26,KPDmeas= 0.2375,KC= 0.2688
Ncalc = 1.5 - 1.54
Help on Optical Data: Optical Data: Uniaxial (+), w=1.478, e=1.484, bire=0.0060.

Calculated Properties of Bentorite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=1.93 gm/cc
note: Specific Gravity of Bentorite =1.85 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0068459104
Boson Index = 0.9931540896
Help on Photoelectric: Photoelectric: PEBentorite = 4.06 barns/electron
U=PEBentorite x rElectron Density= 7.84 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Bentorite is Not Radioactive

Bentorite Classification

Help on  Dana Class: Dana Class: (31)Hydrated Sulfates Containing Hydroxyl or Halogen
  (31.10.02)Dana Group Ettringite Ca6Al2(SO4)3(OH)12•26(H2O) P 63/mmc 6/m 2/m 2/m Bentorite Ca6(Cr,Al)2(SO4)3(OH)12•26(H2O) P 63/mmc 6/m 2/m 2/m Buryatite! Ca3(Si,Fe,Al)[SO4][B(OH)4](OH,O)6•12(H2O) P 31c 3m
Help on  Strunz Class: Strunz Class: 07.DG.15 07 - SULFATES (SELENATES, TELLURATES)
  07.D - Sulfates (selenates, etc.) with additional anions, with H2O
  07.DG -With large and medium sized cations; with NO3, CO3, B(OH)4, SiO4 or IO3
07.DG.15 Bentorite Ca6(Cr,Al)2(SO4)3(OH)12•26(H2O) P 63/mmc 6/m 2/m 2/m
07.DG.15 Charlesite Ca6(Al,Si)2(SO4)2B(OH)4(OH,O)12•26(H2O) P 31c 3m
07.DG.15 Ettringite Ca6Al2(SO4)3(OH)12•26(H2O) P 63/mmc 6/m 2/m 2/m
07.DG.15 Jouravskite Ca3Mn(SO4,CO3)2(OH)6•12(H2O) P 63/m 6/m
07.DG.15 Sturmanite Ca6(Fe,Al,Mn)2(SO4)2[B(OH)4](OH)12•25(H2O) P 31c 3m
07.DG.15 Thaumasite Ca3Si(CO3)(SO4)(OH)6•12(H2O) P 63/m 6/m
07.DG.15 Buryatite! Ca3(Si,Fe,Al)[SO4][B(OH)4](OH,O)6•12(H2O) P 31c 3m
07.DG.15 Carraraite! Ca3Ge(OH)6(SO4)(CO3)•12H2O P 63/m, or P 63 Hex

Other Bentorite Information

Help on References: References: NAME( AntBidBlaNic5) 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 Bentorite :
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: 07.DG.15





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