Mineral phase
IMA name
Chlorites group
Type
Class
silicate mineral
Compound type
phyllosilicate
Comments
Group endmembers are: Donbassite, Cookeite, Sudoite, Clinochlore, Nimite, Baileychlore, Chamosite, Pennantite, Orthochamosite and Borocookeite - Crystal system: Monoclinic 2/m; with some triclinic polymorphs
Chemical composition
Formula
$A_{5-6}T_4Z_{18}\ \ \ \ \ $ where $A = Al, Fe^{2+}, Fe^{3+}, Li, Mg, Mn $, and/or $Ni$,$\ \ \ T = Al, Fe^{3+}, Si,\ \ \ $ and $Z = O $ and $OH$
Chemical formula
(Al,Fe2+,Fe3+,Li,Mg,Mn,Ni,[])6(Al,Fe3+,Si)4(O,OH)18
Elemental formula
(Al)2-5.33 (Fe2+)0-3 (Fe3+)0-0.5 (Li)0-2 (Mg)1-4 (Mn)0-1 (Ni)0-3 (Si)3-4 O18 (H)6-8
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$Al$ Aluminium element 2 - 5.33 constituent element main
$Fe^{2+}$ Iron(II) cation element 0 - 3 constituent element main
$Fe^{3+}$ Iron(III) cation element 0 - 0.5 constituent element main
$Li$ Lithium element 0 - 2 constituent element main
$Mg$ Magnesium element 1 - 4 constituent element main
$Mn$ Manganese element 0 - 1 constituent element main
$Ni$ Nickel element 0 - 3 constituent element main
$Si$ Silicon element 3 - 4 constituent element main
$O$ Oxygen element 18 constituent element main
$H$ Hydrogen element 6 - 8 constituent element main
Composition comments
Common Impurities: Cr, Co, Ti, Ca, Na, K, C, P, S, H2O, ORG
Chemical functions
  Function Number
$(OH)^-$
Chemical bonds
  Bond Number
$O^--H$ 1
Oxides
Formula $Al_{2}O_{3}$ $FeO$ $Fe_{2}O_{3}$ $Li_{2}O$ $MgO$ $MnO$ $NiO$ $SiO_{2}$ $H_{2}O$
Mass fraction (%)

Strunz

Class
silicates (09)
Division
phyllosilicate (09.E)
Family
Phyllosilicates 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)
End-members
Phase type
crystalline
Crystal system
various
Crystal class
various
Crystal class symbol
various
Crystal spacegroup
various
Molar mass
502.73 - 709.44 $g/mol$
Density
2.62 - 3.4 $g/cm^3$
State NTP
solid
Refringence type
biaxial
Refringence sign
positive or negative
Refraction index $n_{\alpha}$
1.57 - 1.67
Pure color
various
Color
Various shades of green; rarely yellow, red, or white
Diaphaneity
transparent to subtranslucent
Luster
various
Links