Constituent
Name
Orthopyroxene Fs23 Wo1
IMA name
Enstatite-Ferrosilite series
Class
silicate mineral
Compound type
inosilicate
Constituent abundance in material
Relevance
main - major
Arrangement
homogeneous in multi-phases
Mass fraction
0.269 $\pm$ 0.004
Chemical composition
Formula
$(Ca_{0.01},Fe^{2+}_{0.23},Mg_{0.76})_2.[SiO_3]_2$
Chemical formula
(Ca)0.02(Fe2+)0.46(Mg)1.52Si2O6
Elemental formula
Ca0.02 (Fe2+)0.46 Mg1.52 Si2 O6
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$Ca$ Calcium element 0.02 1.0 constituent element main
$Fe^{2+}$ Iron(II) cation element 0.46 1.0 constituent element main
$Mg$ Magnesium element 1.52 1.0 constituent element main
$Si$ Silicon element 2 1.0 constituent element main
$O$ Oxygen element 6 1.0 constituent element main
Composition comments
perfect solid solution - Common impurities: Al, $Fe^{3+}$, Na, K, Co, Ni, Mn, Ti, Cr - Hypersthene is old name for mid-way member between Enstatite and Ferrosilite - C
Oxides
Formula $CaO$ $FeO$ $MgO$ $SiO_{2}$
Mass fraction (%)

Strunz

Class
silicates (09)
Division
inosilicate (09.D)
Family
with 2-periodic single chains, Si2O6; pyroxene family (09.DA)
Code
09.DA.05

Dana

Major class
silicates (VIII)
Class
inosilicate single-width unbranched chains, w=1 (65)
Type
with chains P=2 (65.01)
Group
Orthopyroxenes (65.01.02)
Phase type
crystalline
Crystal system
orthorhombic
Crystal class
dipyramidal
Crystal class symbol
mmm (D2h)
Crystal spacegroup
Pbca
Molar mass
200.78 - 263.86 $g/mol$
Density
3.10 - 4.02 $g/cm^3$
Refringence type
biaxial
Refringence sign
positive
Birefringence
0.009 - 0.021
Refraction index $n_{\alpha}$
1.650 - 1.767
Refraction index $n_{\beta}$
1.652 - 1.770
Refraction index $n_{\gamma}$
1.659 - 1.788
Dispersion V
weak to strong (r < v)
Color
colorless, white, greenish white, yellowish green, green, gray, brown, dark brown, black
Diaphaneity
translucent to opaque
Luster
vitreous