If you are having trouble getting your micas & powders completely incorporated into your base, don't feel bad. You are not alone. You can stir your mixture for 15 minutes, 1/2 hour, even an hour and you're still going to have some little specks showing up in your finished product.
So what's the solution? A hand-held mixer. It doesn't have to be a big one, like the kind you use for cooking and baking. A small, battery-operated one will do just fine. And it doesn't take very long, either. But boy, what a difference! The color will come out completely mixed and even.
It makes me wonder - why don't the instructions on the product say to do it this way?
Have you found a different solution?