Thus it is capable of going through the metamorphic processes unscathed, while other minerals around it are being altered to serpentine , biotite and garnets . This characteristic also explains chromites use as a refractory component in the bricks and linings of blast furnaces. Usually magnesium is present in chromite substituting for the iron and in fact a solid solution series exists between chromite and the much rarer mineral magnesiochromite . All chromite specimens in nature contain some magnesium, likewise all natural magnesiochromites contain some iron. Magnesiochromite is grayer in color and in streak and has a slightly lower density than chromite at a specific gravity of 4.2 to 4.4.
Color is brownish black to a deep dark black.
Luster is metallic to greasy. Crystals are opaque. Well formed crystals are rare and chromite is usually found massive or granular. Cleavage is absent. Fracture is conchoidal.