English: Metal cobalt.
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The name is derived from the word ‘kobold’, meaning ’bad spirit’, because this metal was an unwanted discovery in the search for more precious metals like copper, silver and gold.
Cobalt increases the strength and corrosion resistance of steel and makes it easier to cut. Cobalt alloys are used in cutting instruments such as razor blades, surgical instruments etc.
Cobalt blue, which is cobalt aluminate, CoAl2O4, is a colouring pigment used in pottery, porcelain, paints, and photography. Other blue pigments containing Cobalt are a.o. Cobalt stannate, CoSnO3. Some cobalt salts turn to a pink colour in a humid environment, and to blue in a dry environment, hence its use in ‘weather forecasters’.
Vitamin B12 contains cobalt.