Chromium, chemical element, symbol Cr; for physical constants see Periodic Table. Chromium was discovered by L.N. Vauquelin in 1797. It is a steel-gray, lustrous, hard metal. Elemental chromium is prepared by reduction of its oxide with aluminum. It is used in the production of stainless steel, in plating, and in the production of other metal alloys. Many compounds of chromium are used to color glass, as pigments, and as mordants in the textile industry.