Cobalt is a hard, lustrous and a grey metal with symbol Co and atomic number 27. Cobalt is a transition metal with a close packed hexagonal (CPH) crystal structure at room temperature.The name Cobalt was derived from the German word ‘Kobold’, meaning evil spirits. The interest in cobalt’s uses goes back to 2000 B.C. when cobalt was used by Egyptian artisans as a coloring agent.