Constituent
Name
Vermiculite
IMA name
Vermiculite
Class
silicate mineral
Compound type
phyllosilicate
Constituent abundance in material
Relevance
main - major
Arrangement
single phase
Mass fraction
1.0
Chemical composition
Formula
$(Mg,Fe^{2+},Al)_3(Al,Si)_4O_{10}(OH)_2\bullet 4(H_2O)$
Chemical formula
(Mg,Fe2+,Al)3(Al,Si)4O10(OH)2•4(H2O)
Elemental formula
(Al)0-7 (Mg)0-3 (Fe2+)0-3 (Si)0-4 O16 H10
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$Al$ Aluminium element 0 - 7 constituent element main
$Mg$ Magnesium element 0 - 3 constituent element main
$Fe^{2+}$ Iron(II) cation element 0 - 3 constituent element main
$Si$ Silicon element 0 - 4 constituent element main
$O$ Oxygen element 16 constituent element main
$H$ Hydrogen element 10 constituent element main
Composition comments
Strong variation of Si and Al proportion. Common impurities: Na, K, Ca
Chemical functions
  Function Number
$(OH)^-$ 2
Chemical bonds
  Bond Number
$O^--H$ 1
Oxides
Formula $Al_{2}O_{3}$ $FeO$ $MgO$ $SiO_{2}$ $H_{2}O$
Mass fraction (%)

Strunz

Class
silicates (09)
Division
phyllosilicate (09.E)
Family
Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets (09.EC)
Code
09.EC.50

Dana

Major class
silicates (VIII)
Class
phyllosilicate sheets of six-membered rings (71)
Type
with 2:1 layers (71.02)
Group
Mica group (Hydromica subgroup) (71.02.02d)
Code
71.02.02d.03
Phase type
crystalline
Crystal system
monoclinic
Crystal class
prismatic
Crystal class symbol
2/m (C2h)
Crystal spacegroup
C2/m
Texture
monocrystalline
Molar mass
504.19 $g/mol$
Density
2.3-2.7 $g/cm^3$
Refringence type
biaxial
Refringence sign
negative
Birefringence
0.0200
Refraction index $n_{\alpha}$
1.525-1.561
Refraction index $n_{\beta}$
1.545-1.581
Refraction index $n_{\gamma}$
1.545-1.581
Dispersion V
weak, r > v
Color
Colorless, Green, Gray white, Yellow brown, Brown, Yellow
Diaphaneity
translucent
Luster
vitreous