Olivine is a green-colored mineral that is commonly found in igneous rocks such as basalt and gabbro. It is composed of magnesium, iron, and silicate, giving it a distinctive olive green color. Olivine is known for its high density and hardness, making it a valuable mineral in the jewelry industry where it is often cut and polished for use in gemstones. It is also used in industrial applications such as in refractory bricks and as a sand abrasive. Olivine is often found in volcanic rocks and is a common mineral in earth's mantle.