Chromite - Wikipedia
Chromite is found as orthocumulate lenses of chromitite in peridotite from the Earth's mantle.It also occurs in layered ultramafic intrusive rocks. In addition, it is found in metamorphic rocks such as some serpentinites. Ore deposits of chromite form as early magmatic differentiates. It is commonly associated with olivine, magnetite, serpentine, and corundum.