Sepiolite Mineral Data

[Content and History] [Recent Issues] [Back Issues] [Subscriptions] [Contacts]
See Also: [Diamond Crystals] [Excalibur Minerals] [Hudson Institute] [Minerals on CDROM]
Mineral News was founded some twenty years ago and has developed a following of
avid mineral collectors seeking timely information about new finds and other items
of interest to the collector community. Articles are solicited from collector and scientific authors.

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

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),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

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:

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 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - Handbook of Mineralogy (UofA)
12 - MinDAT
13 - MinMax(Deutsch)
14 - MinMax(English)
15 - Mineralienatlas (Deutsch)
16 - QUT Mineral Atlas
17 - Ruff.Info
18 - YupRocks

Search for Sepiolite using:

[ALTAVISTA] [AOL] [All-The-Web] [HotBot] [Ixquick] [MAMMA] [MSN.COM] [Netscape] [Scirus] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Sepiolite :

AA Mineral Specimens

B & L Fine Minerals

Crystalarium.com

Dan Weinrich Fine Minerals

Dan Weinrich Auctions

Dakota Matrix

Desert Winds Gems and Minerals

John Betts Fine Minerals

Mason's Minerals

Mineral News

Mineral of the Month Club

Wrights Rock Shop

Translate Sepiolite Mineral Data :

Ask about Sepiolite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Sepiolite

Mg4Si6O15(OH)2•6(H2O)
Dana No: 74.03.01b.01 Strunz No: 09.EE.25
Locality:

Notes: