Thanks everyone. In the past I have used so called CP stable/safe mica (Green apple) that went brown during gel and then finished up being purple :eh: I don't have much faith when it's advertised as CP safe/stable.
In any case I wanted a purple pencil line and I ending up using Magic Violet Mica and I am happy to say it worked just fine, no morphing at all, hopefully it will be safe/stable if used to colour the soap as well.