Constituent
Name
Ca-exchanged beidellite SbCa-1 size-fraction <1 µm
IMA name
Beidellite
Class
silicate mineral
Compound type
phyllosilicate
Comments
Beidelite has a typical hydration number of 1 - Chemical composition and molecular mass are per half unit cell
Relevance
main - major
Arrangement
homogeneous in multi-phases
Mass fraction
1.0 ± 0.05
Formula
Ca0.25(Al1.91Mg0.03Fe0.09)(Si3.43Al0.57)O10(OH)2
Chemical formula
(Na,Ca0.5)0.3Al2(Si,Al)4O10(OH)2•n(H2O)
Elemental formula
(Ca)0.25-0.15 (Al)2.48-2.5 Mg0.03 Fe0.09 (Si)3.43-4 O12 H2
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
Ca Calcium element 0.25 - 0.15 1.0 constituent element main
Al Aluminium element 2.48 - 2.5 1.0 constituent element main
Mg Magnesium element 0.03 1.0 constituent element main
Fe Iron element 0.09 1.0 constituent element main
Si Silicon element 3.43 - 4 1.0 constituent element main
O Oxygen element 12 1.0 constituent element main
H Hydrogen element 2 1.0 constituent element main
Composition comments
Typical formula: Na0.5Al2.(Si3.5Al0.5)O10(OH)2(H2O) - Common impurities: Ti, K, Mg, Fe - Intermolecular water was not taken into account in atomic composition calculation
Chemical functions
  Function Number
(OH) 2
Chemical bonds
  Bond Number
OH 1
Oxides
Formula SiO2 Al2O3 MgO Fe2O3 CaO H2O
Mass fraction (%) 58.31 31.69 1.09 1.08 2.96 4.87

Strunz

Class
silicates (09)
Division
phyllosilicate (09.E)
Family
with mica sheets, composed of tetrahedral and octahedral nets (09.EC)
Code
09.EC.40

Dana

Major class
silicates (VIII)
Class
phyllosilicate sheets of six-membered rings (71)
Type
with 2:1 clays (71.03)
Group
Smectite group (Dioctahedral Smectites) (71.03.01a)
Code
71.03.01a.01
Phase type
crystalline
Crystal system
monoclinic
Crystal class
prismatic
Crystal class symbol
2/m (C2h)
Crystal spacegroup
C2/m
Texture
cryptocrystalline
Molar mass
369.0 g/mol
Density
N/A g/cm3
Refringence type
biaxial
Refringence sign
negative
Birefringence
0.030 - 0.032
Refraction index nα
1.494 - 1.503
Refraction index nβ
1.525 - 1.532
Refraction index nγ
1.526 - 1.533
Dispersion V
0
Color
white, gray, reddish white, brownish white, pale yellow
Diaphaneity
translucent to subtranslucent
Luster
N/A