Stardust is a greyish green with very subtle gold shimmer. I like to wear it with the Phyto Khol Star Bronze I reviewed here, and I've also pictured that below and in the swatch.
Sisley is very expensive; I can't remember exactly how much the eyeshadow was but I'm pretty sure it was at least £30. I don't buy Sisley outside of the GWP deals they typically have at least a couple of times a year. The GWP sizes are always generous, and make the price of the brand more palatable.