Although it is never found naturally in its free state, cobalt exists all around us in compound forms. These compounds can be found in small quantities in soil, in volcanic emissions, in seawater, in some animals and in the smoke emissions from forest fires. Further afield, cobalt compounds have been found in meteors.
Cobalt that is to be used for commercial purposes, then, has to be removed from the naturally occurring compounds;usually it is sourced as a by-product of the nickel and copper mining industries. The ores in which cobalt may be found include cobaltite, glaucodot, skutterudite and erythrite though there are others. In its pure form, once extracted, cobalt is a whitish ferromagnetic metal. However cobalt compounds in erythrite appear red and in ores containing significant amounts of nickel, cobalt compounds usually appear as green crystals and are known as annabergite.
Only very low quantities of cobalt are found in the earth's crust and waters, some 0.001 % in fact of the earth's crust is made up of cobalt compounds. Cobalt compounds are found to a greater extent within the earth's core. However, the significant point is that those tiny quantities in the earth's crust and in its waters are particularly enduring. In sea waters, for example, the main compound of Cobalt is Cobalt Sulfine (CoS) which is highly insoluble. Similarly, the fact that particles of cobalt compounds can be easily transferred in soil and dust by the wind can be a cause for concern.
In appropriate quantities cobalt can have significant health benefits; quantities of an important cobalt-based compound hydroxocobalamin - is found in Vitamin B12 making it an essential trace element that promotes healthy blood. However, people exposed to high levels of cobalt compounds can be susceptible to asthma or pneumonia. Strict guidelines apply to cobalt exposure within the mining industry worldwide. That said, we are unlikely to encounter dangerous amount of cobalt in our diets.
Like humans, animals gain a small but useful amount of cobalt in their food. However, certain factors can result in animals taking in higher than ideal quantities because of the ease with which cobalt compound particles can enter their food chain through water and the soil, either on the wind or as a result of a forest fire or in an area where animals are grazing on previously volcanic land. . Fortunately, the effects of cobalt are not magnified through the food chain and the effects are unlikely to be passed on to humans consuming the meat of such animals.
Commercially, cobalt and some of its compounds natural and man-made are used in the petrochemical industry and as a component in the manufacture of some alloys which are used for aircraft construction because of its resistance to corrosion.