Chromium is a metallic element with the symbol Cr and atomic number 24. It is a steel-gray, lustrous, hard metal that has a high polish and a high melting point. Chromium is mined as chromite ore. Among its many uses, chromium is used as an alloy to impart corrosion resistance and as used as a plating it imparts a shiny finish. Hexavalent compounds are carcinogenic.