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-temperature conditions and is often used to study the Earth's mantle. This mineral is also a key component of peridot, a gemstone valued for its vibrant green hue. Olivine can be found in various locations around the world, including Hawaii, Arizona, and South Africa. Its unique properties make it an important subject of research in both geology and gemology.