Lovely matte purple
It's rare that you see dark COLORED mattes out there. It's a dark blue based eggplant that looks stunning with shimmering lavenders, light buttery golds (like Urban Decay Blunt), seafoam/mint shadows (like the left side of NARS Habanera shadow duo) and even iridescent aquas (try MAC Steamy eye shadow). I don't get any fall out with this particular shadow (I think because it's matte).
For a pretty and simple look with Cassis, wash a iridescent mint shadow over the lids (the left side of NARS Habanera works well). With a MAC 219 brush, smudge Cassis over the upper lashline and outer corner. Take a clean MAC 217 brush and use to blend the Cassis up into the crease. Take some more Cassis with your 219 and smudge lightly on the outer lower lashline.
***Please see my review on Barefoot Contessa for a general overview of Stila Eye Shadows