Sepiolite Mineral Data

General Sepiolite Information

Chemical Formula: Mg4Si6O15(OH)2•6(H2O) Composition: Molecular Weight = 613.82 gm    Magnesium  15.84 %  Mg   26.26 % MgO    Silicon    27.45 %  Si   58.73 % SiO₂    Hydrogen    1.97 %  H    17.61 % H₂O    Oxygen     54.74 %  O              ______        ______               100.00 %      102.61 % = TOTAL OXIDE Empirical Formula: Mg₄Si₆O₁₅•6(H₂O) Environment: Secondary mineral associated with serpentine. Can precipitate from alkali saline waters in arid environments. IMA Status: Valid Species (Pre-IMA) 1847 Locality: Eski Shehr, Asia Minor. Link to MinDat.org Location Data. Name Origin: From the Greek, sepia - "cuttlefish" and lithos - "stone." From the German, meerschaum meaning "sea froth." Name Pronunciation: Sepiolite + Pronunciation Synonym: ICSD 31142   Meerschaum   PDF 26-1226   Sea Foam  

Sepiolite Image

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Sepiolite Crystallography

Axial Ratios: a:b:c =0.4996:1:0.1964 Cell Dimensions: a = 13.43, b = 26.88, c = 5.281, Z = 4; V = 1,906.43 Den(Calc)= 2.14 Crystal System: Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pnan X Ray Diffraction: By Intensity(I/I_o): 12.3(1), 2.58(0.6), 4.4(0.35), Crystal Structure:

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Post J E , Bish D L , Heaney P J , American Mineralogist , 92 (2007) p.91-97, Synchrotron powder X-ray diffraction study of the structure and dehydration, behavior of sepiolite, Sample: T = 742 K, Locality: Durango, Mexico

 

Physical Properties of Sepiolite

Cleavage: {???} Perfect Color: Grayish white, Yellowish white, Bluish green white, Reddish white, Gray. Density: 2 Diaphaneity: Opaque Fracture: Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz). Habit: Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite). Habit: Fibrous - Crystals made up of fibers. Hardness: 2 - Gypsum Luminescence: Non-fluorescent. Luster: Earthy (Dull) Streak: white  

Optical Properties of Sepiolite

Gladstone-Dale: CI meas= -0.116 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.043 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2446,KPDmeas= 0.2617,KC= 0.2346
Ncalc = 1.47 - 1.5 Optical Data: Biaxial (-), a=1.52, b=1.5202, g=1.53, bire=0.0100, 2V(Calc)=18, 2V(Meas)=20-70. Dispersion none.  

Calculated Properties of Sepiolite

Electron Density: Bulk Density (Electron Density)=2.18 gm/cc
note: Specific Gravity of Sepiolite =2.14 gm/cc.
Fermion Index: Fermion Index = 0.02
Boson Index = 0.98 Photoelectric: PE_Sepiolite = 1.43 barns/electron
U=PE_Sepiolite x rElectron Density= 3.12 barns/cc.
Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Sepiolite is Not Radioactive  

Sepiolite Classification

Dana Class: 74.03.01b.01 (74)Phyllosilicate Modulated Layers   (74.03)with joined strips   (74.03.01b)Palygorskite-sepiolite group (Sepiolite subgroup)  

74.03.01b.01 Sepiolite Mg4Si6O15(OH)2•6(H2O) Pnan 2/m 2/m 2/m

 

74.03.01b.02 Falcondoite (Ni,Mg)4Si6O15(OH)2•6(H2O) Pncn 2/m 2/m 2/m

 

74.03.01b.03 Loughlinite Na2Mg3Si6O16•8(H2O) Unk Ortho

Strunz Class: 09.EE.25 09 - SILICATES (Germanates)   09.E - Phyllosilicates   09.EE -Single tetrahedral nets of 6-membered rings  

09.EE.25 Falcondoite (Ni,Mg)4Si6O15(OH)2•6(H2O) Pncn 2/m 2/m 2/m

 

09.EE.25 Loughlinite Na2Mg3Si6O16•8(H2O) Unk Ortho

 

09.EE.25 Kalifersite! (K,Na)5Fe7Si20O50(OH)6•12(H2O) P1 1

 

09.EE.25 Sepiolite Mg4Si6O15(OH)2•6(H2O) Pnan 2/m 2/m 2/m

 

Other Sepiolite Information

References: NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32) See Also: Links to other databases for Sepiolite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Athena
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - Franklin Minerals(Dunn)
8 - GeoScienceWorld
9 - Google Images
10 - Google Scholar
11 - Handbook of Mineralogy (MinSocAm)
12 - Handbook of Mineralogy (UofA)
13 - MinDAT
14 - Mineralienatlas (Deutsch)
15 - Online Mineral Museum
16 - QUT Mineral Atlas
17 - Ruff.Info
18 - YupRocks
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Ask about Sepiolite here :
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