Constituent chamosite | SSHADE

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Constituent

Name: chamosite
IMA name: Chamosite

Class: silicate mineral
Compound type: phyllosilicate

Constituent abundance in material

Relevance: main - major
Arrangement: single phase
Mass fraction: 1.0 $\pm$ 0.01

Chemical composition

Formula: [ $(Fe_^{2+}_{0.85}Fe_^{3+}_{0.54}Mg_{3.30}Al_{1.10}Mn_{0.01})(Si_{2.74}Al_{1.26})O_{10}(OH)_8$
Chemical formula: (Mg,Fe2+,Fe3+)5Al(Si3Al)O10(OH,O)8
Elemental formula: (Fe2+)0.85-4 (Fe3+)0.54-1 (Mg)3.3-2 (Al)2.36-2 Mn0.01 (Si)2.74-3 O18 H8
Isotope mixture type: terrestrial abundance

	Formula	Name	Family	Number min-max	Isotope mole fraction	State	Relevance
	$Fe^{2+}$	Iron(II) cation	element	0.85 - 4	1.0	constituent element	main
	$Fe^{3+}$	Iron(III) cation	element	0.54 - 1	1.0	constituent element	main
	$Mg$	Magnesium	element	3.3 - 2	1.0	constituent element	main
	$Al$	Aluminium	element	2.36 - 2	1.0	constituent element	main
	$Mn$	Manganese	element	0.01	1.0	constituent element	main
	$Si$	Silicon	element	2.74 - 3	1.0	constituent element	main
	$O$	Oxygen	element	18	1.0	constituent element	main
	$H$	Hydrogen	element	8	1.0	constituent element	main

Composition comments: Fe3+ is minor or nonexistent. Common impurities: Ca, Na

Chemical functions and bonds

Chemical functions

	Function	Number
	$(OH)^-$

Chemical bonds

	Bond	Number
	$O^--H$	1

Oxides composition

Oxides

Formula	$SiO_{2}$	$Al_{2}O_{3}$	$FeO$	$Fe_{2}O_{3}$	$MgO$	$MnO$	$H_{2}O$
Mass fraction (%)	28.04	20.39	10.39	7.37	22.63	0.12	11.94

Oxides comments

Oxides compositions measured by Electron Micro Probe Analysis. H2O content recalculated from the structural formula.

Classifications

Strunz

Class: silicates (09)
Division: phyllosilicate (09.E)
Family: with mica sheets, composed of tetrahedral and octahedral nets (09.EC)
Code: 09.EC.55

Dana

Major class: silicates (VIII)
Class: phyllosilicate sheets of six-membered rings (71)
Type: interlayered 1:1, 2:1, and octahedra (71.04)
Group: Chlorite group (Tri-Dioctahedral) (71.04.01)
Code: 71.04.01.07

Phase type: crystalline

Crystallography

Crystal system: monoclinic
Crystal class: prismatic
Crystal class symbol: 2/m (C2h)
Crystal spacegroup: C2/m

Texture: polycrystalline

Physical properties

Molar mass: 603.0 $g/mol$
Density: N/A $g/cm^3$

Optical properties

Refringence type: biaxial
Refringence sign: negative
Birefringence: 0.0700
Refraction index $n_{\alpha}$: 1.595 - 1.671
Refraction index $n_{\beta}$: 1.599 - 1.684
Refraction index $n_{\gamma}$: 1.599 - 1.685
Dispersion V: r < v weak
Color: Green, Gray, Greenish gray, Brown, Blackish green, black
Diaphaneity: translucent to opaque
Luster: N/A