Olivine

Olivine has the general chemical composition of (Mg,Fe)₂[SiO₄]. It is a very common mineral in igneous rocks and sediments from those rocks. The magnesium end member is the mineral Forsterite and the iron end member is Fayalite. As the amount of iron increases the names chrysolite, hyalosiderite, hortonolite, and ferrohortonolite are used.