Peridot is found in a specific type of rock called dunite. Dunite is an ultramafic rock, which means it's very rich in magnesium and iron. Peridot forms deep within the Earth's mantle and is brought to the surface through volcanic eruptions.

Here's a breakdown:

* Peridot forms: Deep within the Earth's mantle

* Peridot is found in: Dunite

* Dunite is: An ultramafic rock rich in magnesium and iron

* Dunite is brought to the surface by: Volcanic eruptions

While peridot is primarily found in dunite, it can also be found in other ultramafic rocks like:

* Lherzolite: Another type of ultramafic rock.

* Harzburgite: Another type of ultramafic rock.

However, dunite is the most common rock type where you'll find peridot.