Along with the rarer iron-rich fayalite, forsterite is one of the two members of the olivine mineral series. It is defined as olivine that contains more magnesium within its composition than iron and therefore includes the well-known gemstone peridot. However, these terms cannot be used interchangeably as forsterite must possess a green or yellowish-green hue to qualify as peridot.

The mineral was first described in 1824 from samples sourced around Mount Vesuvius, and was named in honour of the eighteenth century English naturalist and mineral collector Adolarius Jacob Forster. Naturally occurring, non-peridot forsterite gemstones tend to be colorless specimens from Myanmar’s famous Mogok gemstone tract, while synthetic blue material is sometimes produced for use as a visually convincing tanzanite simulant. However, peridots make up the vast majority of forsterite-based gemstones that are encountered within the marketplace.