Cobalt is a silver-white, lustrous, hard, brittle metal that is chemically active and rarely occurs uncombined in nature. It is, however, often found in meteoric metal. Cobalt compounds have been used for centuries to impart a rich blue color to glass, glazes, and ceramics. The element has been detected in Egyptian sculpture and Persian jewelry from the third millennium BCE. The word cobalt is derived from the German word for “goblin.” Why was the element thus named? Discuss