Most of these occur along with troctolites, norites, serpentine and peridotite.
In this locality the original rock is a peridotite, relatively low in nickel, which has been altered to serpentine.
peridotite and gabbro form much of the eastern peninsula (Banggai).
In Georgia the asbestos, which is anthophyllite, occurs in lenticular masses in peridotite associated with gneiss.
Chromite is a common minor constituent of basic igneous rocks of the peridotite and pyroxenite type.
Small diamonds have been found in peridotite masses in Pike County, Arkansas, but these are of very little commercial value.