I love this deep rich shade of purple. To mix up this color, I started with a purple base that was equal to the Premo purple (recipe # 10-2). This recipe originally came from the list of recipes provided by Donna Kato on the Shades of Clay site. It is basically Kato violet with a bit of red added. When you mix up this clay color you will discover that it does darken a bit after baking. It is the small amount of red added that causes this. While Kato clay colors do not generally darken after baking like other clay brands do, I have found the red and magenta will both darken so I have learned to adjust my measurements to allow for this.
So here is my recipe for the Pantone color Phlox.
2 parts of recipe mixture # 10-2 (= to Premo Purple)
1 part Kato magenta
If you add 1/2 part pearl to the above recipe, you will end up with just a touch lighter shade but with a bit of shimmer.