Constituent
- Name
- Mg-exchanged beidellite SbId-1 size-fraction <0.1 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
- Formula
- $Mg_{0.20}(Al_{1.89}Mg_{0.1}Fe_{0.05})(Si_{3.59}Al_{0.41})O_{10}(OH)_2$
- Chemical formula
- (Na,Ca0.5)0.3Al2(Si,Al)4O10(OH)2•n(H2O)
- Elemental formula
- (Al)2.3-2.5 Mg0.3 Fe0.05 (Si)3.59-4 O12 H2
- Isotope mixture type
- terrestrial abundance
- Composition comments
- Typical formula: $Na_{0.5}Al_2.(Si_{3.5}Al_{0.5})O_{10}(OH)_2 \bullet (H_2O)$ - Common impurities: Ti, K, Mg, Fe - Intermolecular water was not taken into account in atomic composition calculation
- Oxides
-
Formula $SiO_{2}$ $Al_{2}O_{3}$ $MgO$ $Fe_{2}O_{3}$ $H_{2}O$ Mass fraction (%) 55.84 34.25 3.06 1.95 4.88
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 $g/cm^3$
- Refringence type
- biaxial
- Refringence sign
- negative
- Birefringence
- 0.030 - 0.032
- Refraction index $n_{\alpha}$
- 1.494 - 1.503
- Refraction index $n_{\beta}$
- 1.525 - 1.532
- Refraction index $n_{\gamma}$
- 1.526 - 1.533
- Dispersion V
- 0
- Color
- white, gray, reddish white, brownish white, pale yellow
- Diaphaneity
- translucent to subtranslucent
- Luster
- N/A