(Chemical symbol: Co). A hard metallic element, similar to nickel in appearance but with a bluish hue. It is used for magnetic alloys, high-temperature alloys in steel, and for pigments in glass and ceramics.
Cobalt is malleable, ductile and weakly magnetic. It oxidizes very slowly in moist air. In the metallic form, cobalt does not have many uses, however, when combined with other elements, it is used in hardfacing materials, and also as an alloying agent in steel when high strength or hardness at high temperatures is required. It imparts the quality known as red hardness.
Atomic number: 27; atomic weight: 58.9332; melting point: 1467°C (2673°F); specific gravity: 8.5.