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
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