The mineral olivine () is a magnesium iron silicate with the formula (Mg2+, Fe2+)2. It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickly on the surface. For this reason, olivine has been proposed as a good candidate for accelerated weathering to sequester carbon dioxide from the Earth's oceans and atmosphere, as part of climate change mitigation. Olivine has a number of other historical uses, as gemstones, usually called peridot and chrysolite, and industrially for metal working processes.