Constituent
Name
smectites
Class
silicate mineral
Compound type
phyllosilicate
Comments
Monoclinic clay-like minerals
Relevance
main - major
Arrangement
heterogeneous in multi-phases
Formula
$A_{0.3}D_{2-3}.(T_4O_{10})Z_2 \bullet n(H_2O)$
Chemical formula
A0.3D(2-3)T4O10Z2•n(H2O)
Isotope mixture type
terrestrial abundance
Composition comments
A=Na,Ca,Li; D=Mg,Fe2+,Fe3+,Al,Li,Ni,Zn,Cr,Cu; T=Si,Al; Z=OH,F - Common impurities: Ti, K
Chemical functions
  Function Number
$\bullet (OH)^-$
Chemical bonds
  Bond Number
$O^--H$ 1

Strunz

Class
silicates (09)
Division
phyllosilicate (09.E)
Family
Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets (09.EC)

Dana

Major class
silicates (VIII)
Class
phyllosilicate sheets of six-membered rings (71)
Type
with 2:1 clays (71.03)
Group
N/A (N/A)
Phase type
crystalline
Crystal system
monoclinic
Crystal class
prismatic
Crystal class symbol
2/m (C2h)
Crystal spacegroup
C2/m
Texture
polycrystalline
Molar mass
383.25 - 580.37 $g/mol$
Density
2.0 - 3.0 $g/cm^3$
Refringence type
biaxial
Refringence sign
negative
Birefringence
0.015 - 0.040
Refraction index $n_{\alpha}$
1.479 - 1.58
Dispersion V
none to strong
Diaphaneity
translucent to opaque
Luster
earthy