San Carlos peridotite with chrome diopside and spinel in volcanic basalt, vivid colorLocale: San Carlos Apache Reservation, Arizona Approx dimensions: 2. 25 x 2. 25 x 2" Approx weight: 300g While this material is commonly called peridot in (or on) basalt, it is actually more complex. It would be more accurately called a peridotite xenolith in basalt. Peridot is the gem quality version of the mineral olivine, which is common in our Earths upper mantleand even in space. In comparison, peridotite is a combination of several types of