Olivine is a mineral composed mainly of magnesium and iron silicate. It is typically green in color and is commonly found in igneous rocks, such as basalt and peridotite. Olivine is significant in geology because it forms under high temperatures and pressures, making it a key component of the Earth's mantle. This mineral is also used in various industrial applications, including as a refractory material and in the production of glass and ceramics. Additionally, olivine is sometimes used as a gemstone, known as peridot, which is valued for its vibrant green hue.