MONTMORILLONIT
cCHEMICAL FORMULA:
(Na,Ca)0,3(Al,Mg)2Si4O10(OH)2·n(H2O)
Molecular Agırlığı = 549.07 gm
Sodium 0.84 % Na 1.13 % Na2O
Calcium 0.73 % Ca 1.02 % CaO
Aluminum 9.83 % Al 18.57 % Al2O3
Silicon 20.46 % Si 43.77 % SiO2
Hydrogen 4.04 % H 36.09 % H2O
Oxygen 64.11 % O
______ ______
100.00 % 100.58 % =

Montmorillonite Crystallography

Axial Ratios: Axial Ratios: a:b:c =0.5782:1:1.1129

Cell Dimensions: Cell Dimensions: a = 5.17, b = 8.94, c = 9.95, Z = 1; beta = 99.9° V = 453.04 Den(Calc)= 2.01

Crystal System: Crystal System: Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/m

MONTMORILLONITE CLASIFACTION

Dana Class: Dana Class:
)Phyllosilicate Sheets of Six-Membered Rings
with 2:1 clays
Smectite group (Dioctahedral Smectites)

Beidellite Na0.5Al2(Si3.5Al0.5)O10(OH)2·n(H2O) C 2/m or ORTH 2/m

Montmorillonite (Na,Ca)0,3(Al,Mg)2Si4O10(OH)2·n(H2O) C 2/m 2/m

Nontronite Na0.3Fe2(Si,Al)4O10(OH)2·n(H2O) C 2/m 2/m


Volkonskoite Ca0.3(Cr,Mg,Fe)2(Si,Al)4O10(OH)2·4(H2O) C 2/m 2/m

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

Strunz Class: Strunz Class:
Silicates

Phyllosilicates (layered) Mica like with [Si4O10]4- and related groups

Brammallite ? - Yakhontovite series

Brammallite* (Na,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)] C 2/c 2/m

Brinrobertsite! (Na,K,Ca)x(Al,Fe,Mg)4(Si,Al)8O20(OH)4·3.54(H2O)[x=0.35,n=3.54] pseudo 2/m 2/m

Illite* (K,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)] C 2/m 2/m
Montmorillonite (Na,Ca)0,3(Al,Mg)2Si4O10(OH)2·n(H2O) C 2/m 2/m

Beidellite Na0.5Al2(Si3.5Al0.5)O10(OH)2·n(H2O) C 2/m or ORTH 2/m

Nontronite Na0.3Fe2(Si,Al)4O10(OH)2·n(H2O) C 2/m 2/m

Volkonskoite Ca0.3(Cr,Mg,Fe)2(Si,Al)4O10(OH)2·4(H2O) C 2/m 2/m

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

Yakhontovite (Ca,K)0.5(Cu,Fe,Mg)2Si4O10(OH)2·3(H2O) C 2/m 2/m

OPTICAL PROPORTIES
Gladstone-Dale: Gladstone-Dale: CI

meas= 0.135 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.012 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2595,KPDmeas= 0.2219,KC= 0.2565

Optical Data: Optical Data: Biaxial (-), a=1.485-1.535, b=1.504-1.55, g=1.505-1.55, bire=0.0150-0.0200, 2V(Calc)=0-24, 2V(Meas)=5-30. Dispersion none.

Pleochroism (x): Pleochroism (x): colorless.

Pleochroism (y): Pleochroism (y): colorless.

Pleochroism (z): Pleochroism (z): colorless.

Electron Density:

relectron=2.08 gm/cc
note: rMontmorillonite =2.01 gm/cc.

Fermion Index Fermion Index Fermion Index = 0.00987
Boson Index = 0.99013

Photoelectric: Photoelectric:

PEMontmorillonite = 1.26 barns/electron
U=PEMontmorillonite x relectron= 2.63 barns/cc.

Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Montmorillonite is Not Radioactive