Zinc oxide is a very fine white powder that is non-nano and used for whitening, adhesion and UV protection. It is a perfect addition to mineral makeup, particularly in a foundation. While this is a non-bleeding colorant, if you add too much to your soap it can migrate into other colors in the soap design or stain washcloths. We recommend starting out at 1/16th to 1/8th teaspoon per pound for melt & pour soaps. For cold process, add 1 teaspoon of oxide to 1 tablespoon of a carrier oil like Sweet Almond or Olive Oil and mix well using a mini mixer. To create the color in the sample of cold process soap above, we used 1.25 teaspoons of colorant (about 0.15 oz before dispersing) in 1 pound of soap. For more information on oxides in soap, check out this blog post.
INCI: Zinc Oxide