Cobalt is a chemical element with symbol Co and atomic number 27. Like nickel, cobalt in the Earth's crust is found only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.
Three reasons Cobalt stands out
- 1
Used in magnets and rechargeable batteries.
- 2
Its name comes from the German word for goblin, as medieval miners blamed it for making their copper ore toxic.
- 3
Vitamin B12, which is essential for human health, has an atom of this element at its very centre.
Blue glass, red blood cells, powerful magnets
Cobalt compounds have colored ceramics blue for centuries, long before the metal was understood. Today cobalt appears in heat-resistant superalloys, rechargeable batteries, and strong magnets. Biology needs only traces—vitamin B12 contains a cobalt atom—while excessive exposure is harmful.