Fayalite vs Forsterite
Fayalite and Forsterite belong to the same mineral group and differ on 4 measured properties — density most clearly.
Fayalite vs Forsterite
Fayalite
Fe2SiO4
The iron end of the olivine series — dark, dense, low-melting, and a common product of iron smelting slag.
Forsterite
Mg2SiO4
The magnesium end of the olivine series — a refractory mineral that makes furnace linings and, in gem quality, peridot.
| Property | Fayalite | Forsterite |
|---|---|---|
| Crystal system Categorical values can be listed side by side but not ordered or subtracted. | orthorhombic | orthorhombic |
| Density | 4.32–4.39 g/cm³ higher | 3.21–3.33 g/cm³ |
| Lustre Categorical values can be listed side by side but not ordered or subtracted. | vitreous to resinous | vitreous |
| Melting point | 1205 °C | 1890 °C higher |
| Mohs hardness Mohs hardness is an ordinal scale: values can be ranked, but differences and ratios between them are not meaningful. | 6.5–7 | 7 higher |