Forsterite is the magnesian pole of the continuous series which exists in the family of peridots. The ferrous pole is Fayalite (Fe2 SiO4). Between both is Olivines.
Olivines is silicates with independent tetrahedrons (or nésosilicates, from Greek néso which means island).
Forsterite crystallizes in the orthorhombique system.
Peridots form a continuous series of minerals the composition of which varies of a magnesian pole, a Forsterite, in a ferrous pole, a Fayalite.
The olivine belongs to this series and contains variable proportions of magnesium and iron. She is frequent in basalts and péridotites.
To know more about the mineralogy of Forsterite, see Mindat.org->
