Forsterite is a mineral that belongs to the group of olivine minerals. It has a chemical formula of Mg2SiO4 and is commonly found in metamorphic and ultramafic rocks. Forsterite is also known by other names such as magnesian olivine, chrysolite, and peridote. Chrysolite is a term that is used to describe a gem-quality forsterite that has a yellow or greenish-yellow color. Peridot is a gemstone that is often used in jewelry and is a type of forsterite that is rich in iron. Magnesian olivine is a term that is used to describe a type of forsterite that has a high magnesium content.