The so-called „spinel pigments” are minerals that occur as mixed oxides from magnesium and aluminium. In a thermal process, these are replaced in the chrystal lattice structure by other metals which results in coloured variants that can be used as pigments. By use of these pigments, we can now widen the AURO colour spectrum by a multiple of shades and offer, for example, strong violet, yellow, blue, orange or green colours.