Sepiolite Mineral Data

Sepiolite Mineral Data +

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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."

Synonym:

ICSD 31142

Meerschaum

PDF 26-1226

Sea Foam

Sepiolite Image

Images:

Sepiolite

Comments: Sectile to chalky massive sepiolite.
Location: Pinos Altos, Grant County, New Mexico. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

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

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 12.3(1), 2.58(0.6), 4.4(0.35),

Physical Properties of Sepiolite

Cleavage:

[???] Perfect

Color:

Grayish white, Yellowish white, Bluish green white, Reddish white, Gray.

Density:

Diaphaniety:

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:

None.

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

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:

r_electron=2.18 gm/cc
note: r_Sepiolite=2.14 gm/cc.

Fermion Index

Fermion Index = 0.02892
Boson Index = 0.97108

Photoelectric:

PE_Sepiolite= 1.43 barns/electron
U=PE_Sepiolite x r_electron= 3.12 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Sepiolite is Not Radioactive

Sepiolite Classification

Dana Class:

74.3.1b.1 (74)Phyllosilicate Modulated Layers

(74.3)with joined strips

(74.3.1b)Palygorskite-sepiolite group (Sepiolite subgroup)

74.3.1b.1 Sepiolite Mg4Si6O15(OH)2·6(H2O) Pnan 2/m 2/m 2/m

74.3.1b.2 Falcondoite (Ni,Mg)4Si6O15(OH)2·6(H2O) Pncn 2/m 2/m 2/m

74.3.1b.3 Loughlinite Na2Mg3Si6O16·8(H2O) Unk Ortho

Strunz Class:

VIII/H.33-40 VIII - Silicates

VIII/H - Phyllosilicates (layered) Mica minerals with other simple layers, [Si6O15]6- and others

VIII/H.33 - Tuperssuatsiaite - Loughlinite series

VIII/H.33-10 Tuperssuatsiaite Na(Fe,Mn)3[Si8O20](OH)2·n(H2O) C 2/m Mono

VIII/H.33-20 Palygorskite (Mg,Al)2Si4O10(OH)·4(H2O) C 2/m 2/m

VIII/H.33-30 Yofortierite (Mn,Mg)5Si8O20(OH)2·8-9(H2O) Pn(?) m

VIII/H.33-40 Sepiolite Mg4Si6O15(OH)2·6(H2O) Pnan 2/m 2/m 2/m

VIII/H.33-50 Falcondoite (Ni,Mg)4Si6O15(OH)2·6(H2O) Pncn 2/m 2/m 2/m

VIII/H.33-60 Loughlinite Na2Mg3Si6O16·8(H2O) Unk Ortho

VIII/H.33-80 Intersilite! Na6MnTi[Si10O24(OH)](OH)3·4(H2O) I2/m 2/m

VIII/H.33-90 Kalifersite! (K,Na)5Fe7Si20O50(OH)6·12(H2O) P1 1

Other Sepiolite Information

References:

NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)

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Print or Cut-and-Paste your Sepiolite Specimen Label here :

Sepiolite

Mg4Si6O15(OH)2·6(H2O)
Dana No: 74.3.1b.1 Strunz No: VIII/H.33-40
Locality:

Notes: