Natural Chromite
Chromium oxides are used to provide color to ceramics and are used in conjunction with other compounds to make shades of blue, green, gray and black. Ferrochromium fly ash, and in particular natural
chromite were studied as a source of chromium com- pounds for coloring unglazed ceramic tiles. Chromite resulted to be a low expensive natural colouring agent to make shades from gray to black as a function of amount and particle size distribution of the pigment, and firing conditions.