How can there be so many colors? Because iron and oxygen can combine in many ways. In ceramics we know Fe2O3 as red iron and Fe3O4 as black iron (the latter being the more concentrated form). But would you believe there are 6 others (one is Fe13O19!). And four phases of Fe2O3. Plus more iron hydroxides (yellow iron is Fe(OH)3).
|Materials||Iron Oxide Yellow|
|Materials||Iron Oxide Black|
In ceramics and pottery, colorants are added to glazes as metal oxides, metal-oxide-containing raw materials or as manufactured stains.