Rainbow Dust Sparkle Range - Jewel Sky Blue by Classikool&reg; It can be painted, dusted or added to piping work for cake decorating Gross 15g pot The Rainbow Dust range is a product any cake maker should not be without. The shine and colour effects are completely different to those using common absorption or metallic pigments normally used in the food industry. They consist only of edible, widely approved food colorants and/or iron dioxide.