Constituent
- Name
- Mg-exchanged saponite SAP size-fraction <2 µm
- IMA name
- Saponite
- Class
- silicate mineral
- Compound type
- phyllosilicate
- Comments
- Chemical composition and molecular mass are per half unit cell
- Relevance
- main - major
- Arrangement
- homogeneous in multi-phases
- Mass fraction
- 1.0 $\pm$ 0.05
- Formula
- $Mg_{0.29}(Mg_{3})(Si_{3.42}Al_{0.58})O_{10}(OH)_2$
- Chemical formula
- (Na,Ca0.5)0.3(Mg,Fe2+)3(Si,Al)4O10(OH)2•4(H2O)
- Elemental formula
- (Al)0.58-1.5 (Mg)3.29-3 (Si)3.42-4 (O)12-16 (H)2-10
- Isotope mixture type
- terrestrial abundance
- 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 - Intermolecular water was not taken into account in atomic composition calculation
- Oxides
-
Formula $SiO_{2}$ $Al_{2}O_{3}$ $MgO$ $H_{2}O$ Mass fraction (%) 53.28 7.62 34.39 4.67
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
- Texture
- cryptocrystalline
- Molar mass
- 385.0 $g/mol$
- Density
- N/A $g/cm^3$
- 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
- N/A