Zinc Powder

Zinc powder is used as a natural white/lightening colourant for cold process soap. 
Hydrate the zinc into a paste using distilled water before adding to your soap batter.  
Ensure a smooth paste to eliminate white specks in you final soap product.
Zinc is not absorbed into the skin as it is non nano and non micro (larger than 100nm) and is non irritating and non allergenic.