Constituent
Name
Diopside
Class
silicate mineral
Compound type
inosilicate
Relevance
main - major
Arrangement
heterogeneous in multi-phases
Mass fraction
9.01
Formula
$CaMg.[SiO_3]_2$
Chemical formula
CaMgSi2O6
Elemental formula
Ca Mg Si2 O6
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$Ca$ Calcium element 1 constituent element main
$Mg$ Magnesium element 1 constituent element main
$Si$ Silicon element 2 constituent element main
$O$ Oxygen element 6 constituent element main
Composition comments
Diopside name used for Ca = 90-100%, Mg = 50-100%, Fe = 1-Mg = 50-0%
Oxides
Formula $CaO$ $MgO$ $SiO_{2}$
Mass fraction (%) 25.9 18.61 55.49

Strunz

Class
silicates (09)
Division
inosilicate (09.D)
Family
with 2-periodic single chains, Si2O6; pyroxene family (09.DA)
Code
09.DA.15

Dana

Major class
silicates (VIII)
Class
inosilicate single-width unbranched chains, w=1 (65)
Type
with chains P=2 (65.01)
Group
C2/c clinopyroxenes (Ca clinopyroxenes) (65.01.03a)
Code
65.01.03a.01
Phase type
crystalline
Crystal system
monoclinic
Crystal class
prismatic
Crystal class symbol
2/m (C2h)
Crystal spacegroup
C2/c
Texture
polycrystalline
Molar mass
216.55 $g/mol$
Density
3.25 - 3.55 $g/cm^3$
Refringence type
biaxial
Refringence sign
positive
Birefringence
0.0290 - 0.0300
Refraction index $n_{\alpha}$
1.663 - 1.699
Refraction index $n_{\beta}$
1.671 - 1.705
Refraction index $n_{\gamma}$
1.693 - 1.728
Dispersion V
weak to distinct, r>v
Color
colorless, blue, brown, green, gray
Diaphaneity
transparent to translucent
Luster
vitreous