All of our micas are safe for use in bath bombs. Just keep in mind that they do tend to float on the surface of the water since they are powders and can stick to that ring around the tub.
To help with this you can add in some Polysorbate 80 which allows the micas to blend into the water better.
For more information on using the Polysorbate 80 in bath bombs check out this blog post on black bath bombs. The part on Poly 80 is towards the end of the post under "Update."