Black Iron Oxide
This Colorant is stable in Cold Process soap. They give a solid opaque or matte colour in the products.
They may be used in MP and HP as well.
Mix with a little oil or liquid from the recipe and add it at trace.
LIP Safe Colours and may be used in a range of products like soaps, lipbalms, lipsticks, lotions, creams and butters etc.
This is a very concetrated colour so use carefully.