It is a hard, lustrous, steel-gray, ductile, metallic chemical element, found in various ores. Used in the preparation of magnetic, wear-resistant, and high-strength alloys. Its compounds are used in the production of inks, paints, and varnishes.

A radioactive isotope of cobalt is used in the treatment of cancer, in research etc.

It was named (c.1730) by Georg Brandt (1694 -1768), Swed chemist; term used for the ore by miners, who regarded it as worthless and as injurious because of its arsenic content.