Ordered Peacock Blue (But let's be honest......it's navy!)  
Very happy with my purchase.  Using in a guest bedroom.  These are indeed 'room darkening curtains.'  It becomes light fairly early in the 'morn and needed something to have the guests sleep past 6am.  
Curtains are polyester and they do have a slight sheen to them BUT they are beautiful so I am not going to complain.  
The hem will allow you to make the curtains longer (as I had to do with the 96" curtains I ordered).