Hectorite Mineral Data

General Hectorite Information

Chemical Formula:

Na0,3(Mg,Li)3Si4O10(OH)2

Composition:

Molecular Weight = 383.25 gm

Sodium 2.40 % Na 3.23 % Na₂O

Lithium 0.54 % Li 1.17 % Li₂O

Magnesium 17.12 % Mg 28.39 % MgO

Silicon 29.31 % Si 62.71 % SiO₂

Hydrogen 0.53 % H 4.70 % H₂O

Oxygen 50.10 % O

______ ______

100.00 % 100.21 % = TOTAL OXIDE

Empirical Formula:

Na_0.4Mg_2.7Li_0.3Si₄O₁₀(OH)₂

Environment:

Clay mineral from altered volcanic tuff ash with a high silica content related to hot spring activity. Smectite group mineral.

IMA Status:

Valid Species (Pre-IMA) 1936

Locality:

Company No. 1 mine, 3 miles south of Hector, San Bernardino Co., California. Link to MinDat.org Location Data.

Name Origin:

Named after it's locality.

Name Pronunciation:

Hectorite + Pronunciation

Hectorite Image

Images:

Hectorite

Comments: Pure white paper-like matted masses of hectorite.
Location: near Hector, San Bernardino County, California, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Hectorite Crystallography

Axial Ratios:

a:b:c =0.5718:1:1.7429

Cell Dimensions:

a = 5.25, b = 9.18, c = 16, Z = 3; beta = 99° V = 761.63 Den(Calc)= 2.51

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/m

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

By Intensity(I/I_o): 1.53(1), 4.58(1), 15.8(0.8),

Physical Properties of Hectorite

Cleavage:

{001} Perfect

Color:

White.

Density:

2 - 3, Average = 2.5

Diaphaneity:

Translucent to Opaque

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Habit:

Aggregates - Made of numerous individual crystals or clusters.

Hardness:

1-2 - Between Talc and Gypsum

Luminescence:

Fluorescent, Short UV=weak sky blue, Long UV=bright sky blue.

Luster:

Earthy (Dull)

Streak:

white

Optical Properties of Hectorite

Gladstone-Dale:

CI meas= 0.055 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.058 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2005,KPDmeas= 0.2013,KC= 0.2129
Ncalc = 1.43 - 1.64

Optical Data:

Biaxial (-), a=1.49, b=1.5, g=1.52, bire=0.0300

Pleochroism (x):

colorless.

Pleochroism (y):

colorless.

Pleochroism (z):

colorless.

Calculated Properties of Hectorite

Electron Density:

Bulk Density (Electron Density)=2.50 gm/cc
note: Specific Gravity of Hectorite =2.50 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Hectorite= 1.56 barns/electron
U=PE_Hectorite x rElectron Density= 3.89 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Hectorite is Not Radioactive

Hectorite Classification

Dana Class:

71.03.01b.04 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.03)with 2:1 clays

(71.03.01b)Smectite group (Trioctahedral Smectites)

71.03.01b.01 Sobotkite? (K,Ca0.5)0.33(Mg,Al)3(Si3Al)O10(OH)2•1-5(H2O) Unk. Mono

71.03.01b.02 Saponite (Ca/2,Na)0,3(Mg,Fe)3(Si,Al)4O10(OH)2•4(H2O) C 2/m 2/m

71.03.01b.02a Ferrosaponite! Ca0.3(Fe,Mg,Fe)3(Si,Al)4O10(OH)2•4(H2O) C? Mono

71.03.01b.03 Sauconite Na0,3Zn3(Si,Al)4O10(OH)2•4(H2O) C 2/m 2/m

71.03.01b.04 Hectorite Na0,3(Mg,Li)3Si4O10(OH)2 C 2/m 2/m

71.03.01b.05 Pimelite? Ni3Si4O10(OH)2•4(H2O) Unk. Hex

71.03.01b.06 Stevensite (Ca0.5,Na)0.33(Mg,Fe)3Si4O10(OH)2•n(H2O) Unk (ORTH ?) Mono

71.03.01b.07 Yakhontovite (Ca,K)0.5(Cu,Fe,Mg)2Si4O10(OH)2•3(H2O) C 2/m 2/m

71.03.01b.08 Zincsilite Zn3Si4O10(OH)2•4(H2O)(?) C 2/m ? 2/m

Strunz Class:

09.EC.45 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EC -Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets

09.EC.45 Griffithite* 4(Mg,Fe,Ca)O.(Al,Fe)2O3.5SiO2•7(H2O) Mono

09.EC.45 Hectorite Na0,3(Mg,Li)3Si4O10(OH)2 C 2/m 2/m

09.EC.45 Swinefordite (Li,Ca0.5,Na)0.72(Li,Al,Mg)2.66(Si,Al)4O10(OH,F)2•2(H2O) C 2/m (MON or ORTH) 2/m

09.EC.45 Zincsilite Zn3Si4O10(OH)2•4(H2O)(?) C 2/m ? 2/m

09.EC.45 Saponite (Ca/2,Na)0,3(Mg,Fe)3(Si,Al)4O10(OH)2•4(H2O) C 2/m 2/m

09.EC.45 Sauconite Na0,3Zn3(Si,Al)4O10(OH)2•4(H2O) C 2/m 2/m

09.EC.45 Spadaite MgSiO2(OH)2•(H2O)(?) Ortho

09.EC.45 Sobotkite? (K,Ca0.5)0.33(Mg,Al)3(Si3Al)O10(OH)2•1-5(H2O) Unk. Mono

09.EC.45 Stevensite (Ca0.5,Na)0.33(Mg,Fe)3Si4O10(OH)2•n(H2O) Unk (ORTH ?) Mono

09.EC.45 Ferrosaponite! Ca0.3(Fe,Mg,Fe)3(Si,Al)4O10(OH)2•4(H2O) C? Mono

Other Hectorite Information

References:

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

See Also:

Links to other databases for Hectorite :
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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Hectorite

Na0,3(Mg,Li)3Si4O10(OH)2
Dana No: 71.03.01b.04 Strunz No: 09.EC.45
Locality:

Notes:

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