Mineral phase
IMA name
Keilite
Type
Class
non-silicate mineral
Compound type
sulfide
Chemical composition
Formula
$(Mg,Fe^{2+},Mn)S $
Chemical formula
(Mg,Fe2+,Mn)S
Elemental formula
(Fe2+)0.5-1 (Mg)0-0.5 (Mn)0-0.5 S
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$Fe^{2+}$ Iron(II) cation element 0.5 - 1 constituent element main
$Mg$ Magnesium element 0 - 0.5 constituent element main
$Mn$ Manganese element 0 - 0.5 constituent element main
$S$ Sulfur element 1 constituent element main
Composition comments
Fe is the dominant atom compared to Mg and Mn. Common impurities: Ca,Zn,Cr

Strunz

Class
sulfides - sufosalts (02)
Division
metal sulfides, M:S = 1:1 (and similar) (02.C)
Family
With Sn, Pb, Hg, etc. (02.CD)
Code
02.CD.10

Dana

Major class
sulfides (II)
Class
sulfides - including selenides and tellurides (02)
Type
where Am Bn Xp, with m:p=1:1 (02.08)
Group
Galena group (Isometric: Fm3m) (02.08.01)
Code
02.08.01.09
Phase type
crystalline
Crystal system
isometric (cubic)
Crystal class
hexoctahedral
Crystal class symbol
m-3m (Oh)
Crystal spacegroup
Fm-3m
Molar mass
81.91 $g/mol$
State NTP
solid
Refringence type
isotropic
Refringence sign
no
Pure color
gray
Color
gray
Diaphaneity
opaque
Luster
metallic
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