Occurrences of Chromium

Chromium is almost never found in its elemental state in nature, with the exception of a diamond deposit in Russia. However, this diamond deposit has a reducing environment, which helps produce small quantities of elemental chromium. Commonly it is found in numerous ores, usually in the mineral chromite. Chromite is the complex of FeCr₂O₃, or iron chromium oxide. Chromium is also found in other minerals, including magnesiochromite (MgCr₂O₄). Chromite is found in earth's mantle and is mined most abundantly in South Africa, India, Kazakhstan and Zimbabwe. Through the refining processes, chromite produces both ferrochromium and metallic chromium.

Similar in characteristics and practical uses to vanadium and titanium, pure chromium has a blue-white color. It is very brittle and corrosion resistant. It has three common oxidation states: +2, +3, and +6. The metal ore (principally chromite, FeCr₂O₄ ), is refined by heating in the presence of Si or Al. The resulting ferrosilicon or ferroaluminum compound is separated from the chromium by electrolysis.

Table 1: Chromium is found in many different compounds, all with different uses and properties.