Cobalt and cobalt compounds can be used to make bright and vibrant colours for inks and pigments.
The most famous of these is “cobalt blue”, however the metal is used for other colours including purple, violet, green, light blue, turquoise, pink, brown and yellow.
The famous “cobalt blue” colour is created by mixing cobalt oxide with alumina.
By altering the concentration of cobalt oxide and adding other metal oxides, many colours can be created for use in inks and pigments. These can be used to colour ceramics and glass. Using cobalt compounds for producing colours dates back to ancient Egypt. Cobalt blue glass beads were found inside the sarcophagus in Tutankhamen’s tomb.