Constituent
- Name
- Fayalite
- IMA name
- Fayalite
- Class
- silicate mineral
- Compound type
- nesosilicate
- Comments
- Fayalite: name by extension of (Fe,Mg)2SiO4 in the range Mg=0-10% - Equivalent Space Group: Pbnm (62)
- Relevance
- main - major
- Arrangement
- single phase
- Mass fraction
- 1.0
- Formula
- Fe$^{2+}_{2}$SiO$_{4}$
- Chemical formula
- Fe2SiO4
- Elemental formula
- (Fe2+)2 Si O4
- Isotope mixture type
- terrestrial abundance
- Oxides
-
Formula $FeO$ $SiO_{2}$ Mass fraction (%) 70.51 29.49
Strunz
- Class
- silicates (09)
- Division
- nesosilicate (09.A)
- Family
- Nesosilicates without additional anions; cations in octahedral [6] coordination (09.AC)
- Code
- 09.AC.05
Dana
- Major class
- silicates (VIII)
- Class
- nesosilicate insular SiO4 groups only (51)
- Type
- with all cations in octahedral [6] coordination (51.03)
- Group
- Olivine group (51.03.01)
- Code
- 51.03.01.01
- Phase type
- crystalline
- Crystal system
- orthorhombic
- Crystal class
- dipyramidal
- Crystal class symbol
- mmm (D2h)
- Crystal spacegroup
- Pnma
- Composition order
- ordered
- Texture
- monocrystalline
- Sizes
-
Crystals Min Max Median Width Mass fraction Shape #1 6.0 $mm$ None
- Molar mass
- 203.78 $g/mol$
- Density
- 4.39 $g/cm^3$
- Refringence type
- biaxial
- Refringence sign
- negative
- Birefringence
- 0.0420 - 0.0510
- Refraction index $n_{\alpha}$
- 1.731 - 1.824
- Refraction index $n_{\beta}$
- 1.76 - 1.864
- Refraction index $n_{\gamma}$
- 1.773 - 1.875
- Color
- brown, black
- Diaphaneity
- transparent to translucent
- Luster
- vitreous