MAC's "Nail Trend F/W 2010" collection consisted of 6 nail polishes & one of them was "Rain of Flowers". This might be favourite blurple of all time, it's simply fantastic :-)
It's a deep purple/blue (= therefore blurple) base with lighter purple sparkles. I'd say it's almost a duchrome (blue/purple).
In the bottle, the polish seems more vivid, but once applied to the nail, the sparkles get lost a bit. That's why I decided to add CND "Sapphire Sparkle" as well as CND "Amethyst Sparkle" to really bring them out. I've to say that I'm pretty content with the way this turned out ;-)