Here's why:
* Olivine is a silicate mineral with a high density, typically found in the Earth's mantle.
* Ultramafic rocks are igneous rocks formed from magma with very low silica content. This low silica content allows for the crystallization of high-density minerals like olivine and pyroxene.
* Examples of ultramafic rocks: Peridotite, dunite, and komatiite.
It's important to note that while olivine is a key component of ultramafic rocks, it can also be found in some other rock types, but in smaller amounts.
