(Co, latin Cobaltum)

Cobalt is widely spread in nature and constitutes about 0.001% of the earth's crust. Although it is an important trace element, in large quantities causes various disorders. In sixties of the last century, some breweries have used cobalt to regulate the froth of beer. For people who have largely been consumed this beer were reported nausea, vomiting, and heart problems (cardiomyopathy), which was initially attributed to drunkenness.

Cobalt is often located in the polluted air.

Cobalt is considered as essential trace element in the body and it is a part of the vitamin B12 making its active part. In addition to its role in the vitamin B12 cobalt participate in only a few enzymes, and this is the reason why some authors do not classify it into the essential micronutrients.