Constituent
Name
saponite
IMA name
Saponite
Class
silicate mineral
Compound type
phyllosilicate
Constituent abundance in material
Relevance
main - major
Arrangement
single phase
Mass fraction
1.0
Chemical composition
Formula
$(Na,Ca_{0.5})_{0.3}(Mg,Fe^{2+})_3.(Si,Al)_4O_{10}(OH)_2 \bullet 4(H_2O)$
Chemical formula
(Na,Ca0.5)0.3(Mg,Fe2+)3(Si,Al)4O10(OH)2•4(H2O)
Elemental formula
(Na)0-0.3 (Ca)0-0.15 (Mg)0-3 (Fe2+)0-1 (Al)0-1.5 (Si)2.5-4 (O)12-16 (H)2-10
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$Na$ Sodium element 0 - 0.3 constituent element main
$Ca$ Calcium element 0 - 0.15 constituent element main
$Mg$ Magnesium element 0 - 3 constituent element main
$Fe^{2+}$ Iron(II) cation element 0 - 1 constituent element main
$Al$ Aluminium element 0 - 1.5 constituent element main
$Si$ Silicon element 2.5 - 4 constituent element main
$O$ Oxygen element 12 - 16 constituent element main
$H$ Hydrogen element 2 - 10 constituent element main
Composition comments
Typical formula: $(Ca_{0.1}Na_{0.1})(Mg_{2.25}Fe^{2+}_{0.75}).(Si_3Al)O_{10}(OH)_2 \bullet 4(H_2O)$ - Common impurities: Ti, Mn, Ni, K, P
Chemical functions
  Function Number
$(OH)^-$ 2
Chemical bonds
  Bond Number
$O^--H$ 1
Oxides
Formula $Na_{2}O$ $CaO$ $MgO$ $FeO$ $Al_{2}O_{3}$ $SiO_{2}$ $H_{2}O$
Mass fraction (%)

Strunz

Class
silicates (09)
Division
phyllosilicate (09.E)
Family
with mica sheets, composed of tetrahedral and octahedral nets (09.EC)
Code
09.EC.45

Dana

Major class
silicates (VIII)
Class
phyllosilicate sheets of six-membered rings (71)
Type
with 2:1 clays (71.03)
Group
Smectite group (Trioctahedral Smectites) (71.03.01b)
Code
71.03.01b.02
Phase type
crystalline
Crystal system
monoclinic
Crystal class
prismatic
Crystal class symbol
2/m (C2h)
Crystal spacegroup
C2/m
Molar mass
480.19 $g/mol$
Density
2.3 $g/cm^3$
Refringence type
biaxial
Refringence sign
negative
Birefringence
0.032 - 0.037
Refraction index $n_{\alpha}$
1.479 - 1.49
Refraction index $n_{\beta}$
1.51 - 1.525
Refraction index $n_{\gamma}$
1.511 - 1.527
Color
white, yellowish white, greenish white, reddish white, bluish white
Diaphaneity
subtranslucent to opaque
Luster
earthy