Cobalt

Cobalt blue has been used for centuries in pottery glazes, jewelry, vases, and paints. It was used across ancient civilizations and has been found in the ruins of Pompeii, porcelain from the Tang and Ming dynasties, and ancient Egyptian statues.

In 1730, Swedish chemist Georg Brandt became interested in a dark blue ore that was found in some local copper. He eventually proved that it was a new metal. Cobalt was the first metal to be discovered in the modern era, with all previously known metals having no recorded discoverers.

Cobalt has been known and loved through the ages for its brilliant blue color, but pure cobalt metal is a gray steel color. The blue color comes from cobalt-containing salts, like cobalt aluminate. Beyond its beauty, cobalt is known for its strength and magnetism at high temperatures.

Cobalt is a silver-white, hard, lustrous, and brittle metal.

Beyond having been used for centuries to produce brilliant blue colors, cobalt has some pretty impressive properties, like a high melting point and mechanical strength that make it very useful. When combined with other metals, cobalt produces superalloys (mixed metals) that stay strong even at high temperatures.

One of Cobalt’s superpowers is that it remains magnetic even at very high temperatures. Adding it to other metals makes strong magnets that can get very hot and sometimes that’s useful. For example, samarium cobalt stays magnetic up to 800°C! Cobalt's magnetism is important for recording and storing information on magnetic tapes and hard drives.

Cobalt is also used in newer batteries and to make strong coatings on drills and saws, aircraft turbines, and prosthetic bone replacements.

Cobalt is also part of an important vitamin—vitamin B-12. The vitamin, also known as cobalamin, is essential for making red blood cells, maintaining the nervous system, and stabilizing DNA.

Cobalt compounds include cobalt oxide, cobalt potassium nitrite, cobalt aluminate, and cobalt ammonium phosphate.

One stable cobalt isotope exists in nature—cobalt-59. The other twenty-two isotopes are radioactive, with half-lives ranging from five years to less than a second.

Cobalt-60 is the most long-lived radioactive isotope and is important, medically, as a radiation therapy for cancers.

Cobalt occurs in minerals called cobaltite, smaltite, and erythrite. It is often associated with nickel, silver, lead, copper, and iron ores, from which it is most frequently obtained as a by-product (cobalt is what’s left over after the main metal is mined).

Important ore deposits are found in the Democratic Republic of the Congo, China, Canada, Australia, the Republic of Zambia, and Brazil.